diff --git a/documentation/wiki/ChangeWaves.md b/documentation/wiki/ChangeWaves.md
index 09e7ca1394c..5df8c06508f 100644
--- a/documentation/wiki/ChangeWaves.md
+++ b/documentation/wiki/ChangeWaves.md
@@ -23,6 +23,9 @@ A wave of features is set to "rotate out" (i.e. become standard functionality) t
 
 ## Current Rotation of Change Waves
 
+### 17.14
+- [.SLNX support - use the new parser for .sln and .slnx](https://github.com/dotnet/msbuild/pull/10836)
+
 ### 17.12
 - [Log TaskParameterEvent for scalar parameters](https://github.com/dotnet/msbuild/pull/9908)
 - [Convert.ToString during a property evaluation uses the InvariantCulture for all types](https://github.com/dotnet/msbuild/pull/9874)
diff --git a/eng/BootStrapMsBuild.targets b/eng/BootStrapMsBuild.targets
index dcff8617638..d4330ba658d 100644
--- a/eng/BootStrapMsBuild.targets
+++ b/eng/BootStrapMsBuild.targets
@@ -35,7 +35,8 @@
         <_NuGetRuntimeDependencies Include="%(RuntimeCopyLocalItems.Identity)" Condition="'@(RuntimeCopyLocalItems->Contains('Newtonsoft.Json'))' == 'true'" />
         <_NuGetRuntimeDependencies Include="%(RuntimeCopyLocalItems.Identity)" Condition="'@(RuntimeCopyLocalItems->Contains('NuGetSdkResolver'))' == 'true'" />
         <_NuGetRuntimeDependencies Include="%(RuntimeCopyLocalItems.Identity)" Condition="'@(RuntimeCopyLocalItems->Contains('Microsoft.Extensions.'))' == 'true'" />
-
+        <_NuGetRuntimeDependencies Include="%(RuntimeCopyLocalItems.Identity)" Condition="'@(RuntimeCopyLocalItems->Contains('Microsoft.VisualStudio.SolutionPersistence'))' == 'true'" />
+      
         <!-- NuGet.targets and NuGet.RestoreEx.targets will be in the RuntimeTargetsCopyLocalItems ItemGroup -->
         <_NuGetRuntimeDependencies Include="%(RuntimeTargetsCopyLocalItems.Identity)" Condition="'@(RuntimeTargetsCopyLocalItems->Contains('NuGet.'))' == 'true'" />
 
@@ -48,7 +49,7 @@
 
   <Target Name="RemoveExtraAssemblyReferences" BeforeTargets="ResolveAssemblyReferences">
     <!-- This is really hacky, but these references will cause issues when trying to 'build' this project.
-         To acquire the NuGet binaries we depend on for local run-time ('bootstrap'), we we are using a PackageReference (to
+         To acquire the NuGet binaries we depend on for local run-time ('bootstrap'), we are using a PackageReference (to
          'NuGet.Build.Tasks' and 'Microsoft.Build.NuGetSdkResolver'). This has the advantage of using NuGets compatibility
          check to ensure we choose the right version of those assemblies. But, at 'bootstrap' time these runtime dependencies
          need to be in a specific location that does not mesh with NuGet. To resolve this, we include the default
diff --git a/src/Build.OM.UnitTests/Construction/SolutionFile_Tests.cs b/src/Build.OM.UnitTests/Construction/SolutionFile_Tests.cs
index d6abd900521..fcf15461cc3 100644
--- a/src/Build.OM.UnitTests/Construction/SolutionFile_Tests.cs
+++ b/src/Build.OM.UnitTests/Construction/SolutionFile_Tests.cs
@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -31,31 +32,31 @@ public class SolutionFile_Tests
         [Fact]
         public void ParseSolution_VC()
         {
+            string solutionFileContents =
+            """
+            Microsoft Visual Studio Solution File, Format Version 9.00
+            # Visual Studio 2005
+            Project('{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}') = 'Project name.vcproj', 'Relative path\to\Project name.vcproj', '{0ABED153-9451-483C-8140-9E8D7306B216}'
+            EndProject
+            Global
+                GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                    Debug|AnyCPU = Debug|AnyCPU
+                    Release|AnyCPU = Release|AnyCPU
+                EndGlobalSection
+                GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                    {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.ActiveCfg = Debug|AnyCPU
+                    {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.Build.0 = Debug|AnyCPU
+                    {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.ActiveCfg = Release|AnyCPU
+                    {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.Build.0 = Release|AnyCPU
+                EndGlobalSection
+                GlobalSection(SolutionProperties) = preSolution
+                    HideSolutionNode = FALSE
+                EndGlobalSection
+            EndGlobalf
+            """;
+
             Assert.Throws<InvalidProjectFileException>(() =>
             {
-                string solutionFileContents =
-                    @"
-                Microsoft Visual Studio Solution File, Format Version 9.00
-                # Visual Studio 2005
-                Project('{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}') = 'Project name.vcproj', 'Relative path\to\Project name.vcproj', '{0ABED153-9451-483C-8140-9E8D7306B216}'
-                EndProject
-                Global
-                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-                        Debug|AnyCPU = Debug|AnyCPU
-                        Release|AnyCPU = Release|AnyCPU
-                    EndGlobalSection
-                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.ActiveCfg = Debug|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.Build.0 = Debug|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.ActiveCfg = Release|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.Build.0 = Release|AnyCPU
-                    EndGlobalSection
-                    GlobalSection(SolutionProperties) = preSolution
-                        HideSolutionNode = FALSE
-                    EndGlobalSection
-                EndGlobal
-                ";
-
                 ParseSolutionHelper(solutionFileContents);
                 Assert.Fail("Should not get here");
             });
@@ -96,7 +97,7 @@ public void ParseSolution_VC2(bool convertToSlnx)
 
             string expectedProjectName = convertToSlnx ? "Project name" : "Project name.myvctype";
             Assert.Equal(expectedProjectName, solution.ProjectsInOrder[0].ProjectName);
-            Assert.Equal(ConvertToUnixPathIfNeeded("Relative path\\to\\Project name.myvctype", convertToSlnx), solution.ProjectsInOrder[0].RelativePath);
+            Assert.Equal(ConvertToUnixPathIfNeeded("Relative path\\to\\Project name.myvctype"), solution.ProjectsInOrder[0].RelativePath);
             if (!convertToSlnx)
             {
                 // When converting to SLNX, the project GUID is not preserved.
@@ -104,42 +105,6 @@ public void ParseSolution_VC2(bool convertToSlnx)
             }
         }
 
-        /// <summary>
-        /// A slightly more complicated test where there is some different whitespace.
-        /// </summary>
-        [Fact]
-        public void ParseSolutionWithDifferentSpacing()
-        {
-            string solutionFileContents =
-                @"
-                Microsoft Visual Studio Solution File, Format Version 9.00
-                # Visual Studio 2005
-                Project(' { Project GUID} ')  = ' Project name ',  ' Relative path to project file '    , ' {0ABED153-9451-483C-8140-9E8D7306B216} '
-                EndProject
-                Global
-                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-                        Debug|AnyCPU = Debug|AnyCPU
-                        Release|AnyCPU = Release|AnyCPU
-                    EndGlobalSection
-                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.ActiveCfg = Debug|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.Build.0 = Debug|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.ActiveCfg = Release|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.Build.0 = Release|AnyCPU
-                    EndGlobalSection
-                    GlobalSection(SolutionProperties) = preSolution
-                        HideSolutionNode = FALSE
-                    EndGlobalSection
-                EndGlobal
-                ";
-
-            SolutionFile solution = ParseSolutionHelper(solutionFileContents);
-
-            Assert.Equal("Project name", solution.ProjectsInOrder[0].ProjectName);
-            Assert.Equal("Relative path to project file", solution.ProjectsInOrder[0].RelativePath);
-            Assert.Equal("{0ABED153-9451-483C-8140-9E8D7306B216}", solution.ProjectsInOrder[0].ProjectGuid);
-        }
-
         /// <summary>
         /// Solution with an empty project name.  This is somewhat malformed, but we should
         /// still behave reasonably instead of crashing.
@@ -148,146 +113,33 @@ public void ParseSolutionWithDifferentSpacing()
         public void ParseSolution_EmptyProjectName()
         {
             string solutionFileContents =
-                           @"
-                Microsoft Visual Studio Solution File, Format Version 9.00
-                # Visual Studio 2005
-                Project('{Project GUID}') = '', 'src\.proj', '{0ABED153-9451-483C-8140-9E8D7306B216}'
-                EndProject
-                Global
-                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-                        Debug|AnyCPU = Debug|AnyCPU
-                        Release|AnyCPU = Release|AnyCPU
-                    EndGlobalSection
-                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.ActiveCfg = Debug|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.Build.0 = Debug|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.ActiveCfg = Release|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.Build.0 = Release|AnyCPU
-                    EndGlobalSection
-                    GlobalSection(SolutionProperties) = preSolution
-                        HideSolutionNode = FALSE
-                    EndGlobalSection
-                EndGlobal
-                ";
-
-            SolutionFile solution = ParseSolutionHelper(solutionFileContents);
-
-            Assert.StartsWith("EmptyProjectName", solution.ProjectsInOrder[0].ProjectName);
-            Assert.Equal("src\\.proj", solution.ProjectsInOrder[0].RelativePath);
-            Assert.Equal("{0ABED153-9451-483C-8140-9E8D7306B216}", solution.ProjectsInOrder[0].ProjectGuid);
-        }
-
-        /// <summary>
-        /// Test some characters that are valid in a file name but that also could be
-        /// considered a delimiter by a parser. Does quoting work for special characters?
-        /// </summary>
-        [Fact]
-        public void ParseSolutionWhereProjectNameHasSpecialCharacters()
-        {
-            string solutionFileContents =
-                           @"
-                Microsoft Visual Studio Solution File, Format Version 9.00
-                # Visual Studio 2005
-                Project('{Project GUID}')  = 'MyProject,(=IsGreat)',  'Relative path to project file'    , '{0ABED153-9451-483C-8140-9E8D7306B216}'
-                EndProject
-                Global
-                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-                        Debug|AnyCPU = Debug|AnyCPU
-                        Release|AnyCPU = Release|AnyCPU
-                    EndGlobalSection
-                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.ActiveCfg = Debug|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.Build.0 = Debug|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.ActiveCfg = Release|AnyCPU
-                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.Build.0 = Release|AnyCPU
-                    EndGlobalSection
-                    GlobalSection(SolutionProperties) = preSolution
-                        HideSolutionNode = FALSE
-                    EndGlobalSection
-                EndGlobal
-                ";
-
-            SolutionFile solution = ParseSolutionHelper(solutionFileContents);
-
-            Assert.Equal("MyProject,(=IsGreat)", solution.ProjectsInOrder[0].ProjectName);
-            Assert.Equal("Relative path to project file", solution.ProjectsInOrder[0].RelativePath);
-            Assert.Equal("{0ABED153-9451-483C-8140-9E8D7306B216}", solution.ProjectsInOrder[0].ProjectGuid);
-        }
+            """
+            Microsoft Visual Studio Solution File, Format Version 9.00
+            # Visual Studio 2005
+            Project('{Project GUID}') = '', 'src\.proj', '{0ABED153-9451-483C-8140-9E8D7306B216}'
+            EndProject
+            Global
+                GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                    Debug|AnyCPU = Debug|AnyCPU
+                    Release|AnyCPU = Release|AnyCPU
+                EndGlobalSection
+                GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                    {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.ActiveCfg = Debug|AnyCPU
+                    {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.Build.0 = Debug|AnyCPU
+                    {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.ActiveCfg = Release|AnyCPU
+                    {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.Build.0 = Release|AnyCPU
+                EndGlobalSection
+                GlobalSection(SolutionProperties) = preSolution
+                    HideSolutionNode = FALSE
+                EndGlobalSection
+            EndGlobal
+            """;
 
-        /// <summary>
-        /// Ensure that a bogus version stamp in the .SLN file results in an
-        /// InvalidProjectFileException.
-        /// </summary>
-        [Fact]
-        public void BadVersionStamp()
-        {
-            Assert.Throws<InvalidProjectFileException>(() =>
-            {
-                string solutionFileContents =
-                    @"
-                Microsoft Visual Studio Solution File, Format Version a.b
-                # Visual Studio 2005
-                ";
-
-                ParseSolutionHelper(solutionFileContents);
-            });
-        }
-        /// <summary>
-        /// Expected version numbers less than 7 to cause an invalid project file exception.
-        /// </summary>
-        [Fact]
-        public void VersionTooLow()
-        {
             Assert.Throws<InvalidProjectFileException>(() =>
             {
-                string solutionFileContents =
-                    @"
-                Microsoft Visual Studio Solution File, Format Version 6.0
-                # Visual Studio 2005
-                ";
-
-                ParseSolutionHelper(solutionFileContents);
+                SolutionFile solution = ParseSolutionHelper(solutionFileContents);
             });
         }
-        /// <summary>
-        /// Test to parse a very basic .sln file to validate that description property in a solution file
-        /// is properly handled.
-        /// </summary>
-        [Fact]
-        public void ParseSolutionFileWithDescriptionInformation()
-        {
-            string solutionFileContents =
-                @"
-                Microsoft Visual Studio Solution File, Format Version 9.00
-                # Visual Studio 2005
-                Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'AnyProject', 'AnyProject\AnyProject.csproj', '{2CAB0FBD-15D8-458B-8E63-1B5B840E9798}'
-                EndProject
-                Global
-	                GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		                Debug|Any CPU = Debug|Any CPU
-		                Release|Any CPU = Release|Any CPU
-		                Description = Some description of this solution
-	                EndGlobalSection
-	                GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		                {2CAB0FBD-15D8-458B-8E63-1B5B840E9798}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		                {2CAB0FBD-15D8-458B-8E63-1B5B840E9798}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		                {2CAB0FBD-15D8-458B-8E63-1B5B840E9798}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		                {2CAB0FBD-15D8-458B-8E63-1B5B840E9798}.Release|Any CPU.Build.0 = Release|Any CPU
-	                EndGlobalSection
-	                GlobalSection(SolutionProperties) = preSolution
-		                HideSolutionNode = FALSE
-	                EndGlobalSection
-                EndGlobal
-                ";
-            try
-            {
-                ParseSolutionHelper(solutionFileContents);
-            }
-            catch (Exception ex)
-            {
-                Assert.Fail("Failed to parse solution containing description information. Error: " + ex.Message);
-            }
-        }
 
         /// <summary>
         /// Tests the parsing of a very basic .SLN file with three independent projects.
@@ -338,17 +190,17 @@ public void BasicSolution(bool convertToSlnx)
 
             // When converting to slnx, the order of the projects is not preserved.
             ProjectInSolution consoleApplication1 = solution.ProjectsInOrder.First(p => p.ProjectName == "ConsoleApplication1");
-            Assert.Equal(ConvertToUnixPathIfNeeded("ConsoleApplication1\\ConsoleApplication1.vbproj", convertToSlnx), consoleApplication1.RelativePath);
+            Assert.Equal(ConvertToUnixPathIfNeeded("ConsoleApplication1\\ConsoleApplication1.vbproj"), consoleApplication1.RelativePath);
             Assert.Empty(consoleApplication1.Dependencies);
             Assert.Null(consoleApplication1.ParentProjectGuid);
 
             ProjectInSolution vbClassLibrary = solution.ProjectsInOrder.First(p => p.ProjectName == "vbClassLibrary");
-            Assert.Equal(ConvertToUnixPathIfNeeded("vbClassLibrary\\vbClassLibrary.vbproj", convertToSlnx), vbClassLibrary.RelativePath);
+            Assert.Equal(ConvertToUnixPathIfNeeded("vbClassLibrary\\vbClassLibrary.vbproj"), vbClassLibrary.RelativePath);
             Assert.Empty(vbClassLibrary.Dependencies);
             Assert.Null(vbClassLibrary.ParentProjectGuid);
 
             ProjectInSolution classLibrary1 = solution.ProjectsInOrder.First(p => p.ProjectName == "ClassLibrary1");
-            Assert.Equal(ConvertToUnixPathIfNeeded("ClassLibrary1\\ClassLibrary1.csproj", convertToSlnx), classLibrary1.RelativePath);
+            Assert.Equal(ConvertToUnixPathIfNeeded("ClassLibrary1\\ClassLibrary1.csproj"), classLibrary1.RelativePath);
             Assert.Empty(classLibrary1.Dependencies);
             Assert.Null(classLibrary1.ParentProjectGuid);
 
@@ -365,88 +217,10 @@ public void BasicSolution(bool convertToSlnx)
         /// solution folders will get correctly uniquified.
         /// For the new parser, solution folders are not included to ProjectsInOrder or ProjectsByGuid.
         /// </summary>
-        [Fact]
-        public void SolutionFolders()
-        {
-            string solutionFileContents =
-                @"
-                Microsoft Visual Studio Solution File, Format Version 9.00
-                # Visual Studio 2005
-                Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'ClassLibrary1\ClassLibrary1.csproj', '{34E0D07D-CF8F-459D-9449-C4188D8C5564}'
-                EndProject
-                Project('{2150E333-8FDC-42A3-9474-1A3956D46DE8}') = 'MySlnFolder', 'MySlnFolder', '{E0F97730-25D2-418A-A7BD-02CAFDC6E470}'
-                EndProject
-                Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'MyPhysicalFolder\ClassLibrary1\ClassLibrary1.csproj', '{A5EE8128-B08E-4533-86C5-E46714981680}'
-                EndProject
-                Project('{2150E333-8FDC-42A3-9474-1A3956D46DE8}') = 'MySubSlnFolder', 'MySubSlnFolder', '{2AE8D6C4-FB43-430C-8AEB-15E5EEDAAE4B}'
-                EndProject
-                Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary2', 'ClassLibrary2\ClassLibrary2.csproj', '{6DB98C35-FDCC-4818-B5D4-1F0A385FDFD4}'
-                EndProject
-                Global
-                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-                        Debug|Any CPU = Debug|Any CPU
-                        Release|Any CPU = Release|Any CPU
-                    EndGlobalSection
-                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
-                        {34E0D07D-CF8F-459D-9449-C4188D8C5564}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-                        {34E0D07D-CF8F-459D-9449-C4188D8C5564}.Debug|Any CPU.Build.0 = Debug|Any CPU
-                        {34E0D07D-CF8F-459D-9449-C4188D8C5564}.Release|Any CPU.ActiveCfg = Release|Any CPU
-                        {34E0D07D-CF8F-459D-9449-C4188D8C5564}.Release|Any CPU.Build.0 = Release|Any CPU
-                        {A5EE8128-B08E-4533-86C5-E46714981680}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-                        {A5EE8128-B08E-4533-86C5-E46714981680}.Debug|Any CPU.Build.0 = Debug|Any CPU
-                        {A5EE8128-B08E-4533-86C5-E46714981680}.Release|Any CPU.ActiveCfg = Release|Any CPU
-                        {A5EE8128-B08E-4533-86C5-E46714981680}.Release|Any CPU.Build.0 = Release|Any CPU
-                        {6DB98C35-FDCC-4818-B5D4-1F0A385FDFD4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-                        {6DB98C35-FDCC-4818-B5D4-1F0A385FDFD4}.Debug|Any CPU.Build.0 = Debug|Any CPU
-                        {6DB98C35-FDCC-4818-B5D4-1F0A385FDFD4}.Release|Any CPU.ActiveCfg = Release|Any CPU
-                        {6DB98C35-FDCC-4818-B5D4-1F0A385FDFD4}.Release|Any CPU.Build.0 = Release|Any CPU
-                    EndGlobalSection
-                    GlobalSection(SolutionProperties) = preSolution
-                        HideSolutionNode = FALSE
-                    EndGlobalSection
-                    GlobalSection(NestedProjects) = preSolution
-                        {A5EE8128-B08E-4533-86C5-E46714981680} = {E0F97730-25D2-418A-A7BD-02CAFDC6E470}
-                        {2AE8D6C4-FB43-430C-8AEB-15E5EEDAAE4B} = {E0F97730-25D2-418A-A7BD-02CAFDC6E470}
-                        {6DB98C35-FDCC-4818-B5D4-1F0A385FDFD4} = {2AE8D6C4-FB43-430C-8AEB-15E5EEDAAE4B}
-                    EndGlobalSection
-                EndGlobal
-                ";
-
-            SolutionFile solution = ParseSolutionHelper(solutionFileContents);
-
-            Assert.Equal(5, solution.ProjectsInOrder.Count);
-
-            Assert.Equal(ConvertToUnixPathIfNeeded("ClassLibrary1\\ClassLibrary1.csproj", false), solution.ProjectsInOrder[0].RelativePath);
-            Assert.Equal("{34E0D07D-CF8F-459D-9449-C4188D8C5564}", solution.ProjectsInOrder[0].ProjectGuid);
-            Assert.Empty(solution.ProjectsInOrder[0].Dependencies);
-            Assert.Null(solution.ProjectsInOrder[0].ParentProjectGuid);
-
-            Assert.Equal("{E0F97730-25D2-418A-A7BD-02CAFDC6E470}", solution.ProjectsInOrder[1].ProjectGuid);
-            Assert.Empty(solution.ProjectsInOrder[1].Dependencies);
-            Assert.Null(solution.ProjectsInOrder[1].ParentProjectGuid);
-
-            Assert.Equal(ConvertToUnixPathIfNeeded("MyPhysicalFolder\\ClassLibrary1\\ClassLibrary1.csproj", false), solution.ProjectsInOrder[2].RelativePath);
-            Assert.Equal("{A5EE8128-B08E-4533-86C5-E46714981680}", solution.ProjectsInOrder[2].ProjectGuid);
-            Assert.Empty(solution.ProjectsInOrder[2].Dependencies);
-            Assert.Equal("{E0F97730-25D2-418A-A7BD-02CAFDC6E470}", solution.ProjectsInOrder[2].ParentProjectGuid);
-
-            Assert.Equal("{2AE8D6C4-FB43-430C-8AEB-15E5EEDAAE4B}", solution.ProjectsInOrder[3].ProjectGuid);
-            Assert.Empty(solution.ProjectsInOrder[3].Dependencies);
-            Assert.Equal("{E0F97730-25D2-418A-A7BD-02CAFDC6E470}", solution.ProjectsInOrder[3].ParentProjectGuid);
-
-            Assert.Equal(ConvertToUnixPathIfNeeded("ClassLibrary2\\ClassLibrary2.csproj", false), solution.ProjectsInOrder[4].RelativePath);
-            Assert.Equal("{6DB98C35-FDCC-4818-B5D4-1F0A385FDFD4}", solution.ProjectsInOrder[4].ProjectGuid);
-            Assert.Empty(solution.ProjectsInOrder[4].Dependencies);
-            Assert.Equal("{2AE8D6C4-FB43-430C-8AEB-15E5EEDAAE4B}", solution.ProjectsInOrder[4].ParentProjectGuid);
-        }
-
-        /// <summary>
-        /// Exercises solution folders, and makes sure that samely named projects in different
-        /// solution folders will get correctly uniquified.
-        /// For the new parser, solution folders are not included to ProjectsInOrder or ProjectsByGuid.
-        /// </summary>
-        [Fact]
-        public void SolutionFoldersSlnx()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void SolutionFolders(bool convertToSlnx)
         {
             string solutionFileContents =
                 """
@@ -492,164 +266,38 @@ public void SolutionFoldersSlnx()
                 EndGlobal
                 """;
 
-            SolutionFile solution = ParseSolutionHelper(solutionFileContents, true);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, convertToSlnx);
 
             Assert.Equal(3, solution.ProjectsInOrder.Count);
 
             var classLibrary1 = solution.ProjectsInOrder
-                .FirstOrDefault(p => p.RelativePath == ConvertToUnixPathIfNeeded("ClassLibrary1\\ClassLibrary1.csproj", true));
+                .FirstOrDefault(p => p.RelativePath == ConvertToUnixPathIfNeeded("ClassLibrary1\\ClassLibrary1.csproj"));
             Assert.NotNull(classLibrary1);
             Assert.Empty(classLibrary1.Dependencies);
             Assert.Null(classLibrary1.ParentProjectGuid);
 
             var myPhysicalFolderClassLibrary1 = solution.ProjectsInOrder
-                .FirstOrDefault(p => p.RelativePath == ConvertToUnixPathIfNeeded("MyPhysicalFolder\\ClassLibrary1\\ClassLibrary1.csproj", true));
+                .FirstOrDefault(p => p.RelativePath == ConvertToUnixPathIfNeeded("MyPhysicalFolder\\ClassLibrary1\\ClassLibrary1.csproj"));
             Assert.NotNull(myPhysicalFolderClassLibrary1);
             Assert.Empty(myPhysicalFolderClassLibrary1.Dependencies);
 
             var classLibrary2 = solution.ProjectsInOrder
-                .FirstOrDefault(p => p.RelativePath == ConvertToUnixPathIfNeeded("ClassLibrary2\\ClassLibrary2.csproj", true));
+                .FirstOrDefault(p => p.RelativePath == ConvertToUnixPathIfNeeded("ClassLibrary2\\ClassLibrary2.csproj"));
             Assert.NotNull(classLibrary2);
             Assert.Empty(classLibrary2.Dependencies);
 
             // When converting to slnx, the guids are not preserved.
-            // try at list assert not null
-            Assert.NotNull(myPhysicalFolderClassLibrary1.ParentProjectGuid);
-            Assert.NotNull(classLibrary2.ParentProjectGuid);
-        }
-
-        /// <summary>
-        /// Exercises shared projects.
-        /// </summary>
-        [Fact]
-        public void SharedProjects()
-        {
-            string solutionFileContents =
-                @"
-                Microsoft Visual Studio Solution File, Format Version 12.00
-                # Visual Studio 15
-                VisualStudioVersion = 15.0.27610.1
-                MinimumVisualStudioVersion = 10.0.40219.1
-                Project('{D954291E-2A0B-460D-934E-DC6B0785DB48}') = 'SharedProject1', 'SharedProject1\SharedProject1.shproj', '{14686F51-D0C2-4832-BBAA-6FBAEC676995}'
-                EndProject
-                Project('{D954291E-2A0B-460D-934E-DC6B0785DB48}') = 'SharedProject2', 'SharedProject2\SharedProject2.shproj', '{BAE750E8-4656-4947-B06B-3961E1051DF7}'
-                EndProject
-                Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'ClassLibrary1\ClassLibrary1.csproj', '{3A0EC360-A42A-417F-BDEF-619682CF6119}'
-                EndProject
-                Project('{F184B08F-C81C-45F6-A57F-5ABD9991F28F}') = 'ClassLibrary2', 'ClassLibrary2\ClassLibrary2.vbproj', '{6DEF6DE8-FBF0-4240-B469-282DEE87899C}'
-                EndProject
-                Global
-                    GlobalSection(SharedMSBuildProjectFiles) = preSolution
-                        SharedProject1\SharedProject1.projitems*{14686f51-d0c2-4832-bbaa-6fbaec676995}*SharedItemsImports = 13
-                        SharedProject1\SharedProject1.projitems*{3a0ec360-a42a-417f-bdef-619682cf6119}*SharedItemsImports = 4
-                        SharedProject2\SharedProject2.projitems*{6def6de8-fbf0-4240-b469-282dee87899c}*SharedItemsImports = 4
-                        SharedProject2\SharedProject2.projitems*{bae750e8-4656-4947-b06b-3961e1051df7}*SharedItemsImports = 13
-                    EndGlobalSection
-                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-                        Debug|Any CPU = Debug|Any CPU
-                        Release|Any CPU = Release|Any CPU
-                    EndGlobalSection
-                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
-                        {3A0EC360-A42A-417F-BDEF-619682CF6119}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-                        {3A0EC360-A42A-417F-BDEF-619682CF6119}.Debug|Any CPU.Build.0 = Debug|Any CPU
-                        {3A0EC360-A42A-417F-BDEF-619682CF6119}.Release|Any CPU.ActiveCfg = Release|Any CPU
-                        {3A0EC360-A42A-417F-BDEF-619682CF6119}.Release|Any CPU.Build.0 = Release|Any CPU
-                        {6DEF6DE8-FBF0-4240-B469-282DEE87899C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-                        {6DEF6DE8-FBF0-4240-B469-282DEE87899C}.Debug|Any CPU.Build.0 = Debug|Any CPU
-                        {6DEF6DE8-FBF0-4240-B469-282DEE87899C}.Release|Any CPU.ActiveCfg = Release|Any CPU
-                        {6DEF6DE8-FBF0-4240-B469-282DEE87899C}.Release|Any CPU.Build.0 = Release|Any CPU
-                    EndGlobalSection
-                    GlobalSection(SolutionProperties) = preSolution
-                        HideSolutionNode = FALSE
-                    EndGlobalSection
-                    GlobalSection(ExtensibilityGlobals) = postSolution
-                        SolutionGuid = {1B671EF6-A62A-4497-8351-3EE8679CA86F}
-                    EndGlobalSection
-                EndGlobal
-                ";
-
-            SolutionFile solution = ParseSolutionHelper(solutionFileContents);
-
-            Assert.Equal(4, solution.ProjectsInOrder.Count);
-
-            Assert.Equal(@"SharedProject1\SharedProject1.shproj", solution.ProjectsInOrder[0].RelativePath);
-            Assert.Equal("{14686F51-D0C2-4832-BBAA-6FBAEC676995}", solution.ProjectsInOrder[0].ProjectGuid);
-            Assert.Empty(solution.ProjectsInOrder[0].Dependencies);
-            Assert.Null(solution.ProjectsInOrder[0].ParentProjectGuid);
-
-            Assert.Equal(@"SharedProject2\SharedProject2.shproj", solution.ProjectsInOrder[1].RelativePath);
-            Assert.Equal("{BAE750E8-4656-4947-B06B-3961E1051DF7}", solution.ProjectsInOrder[1].ProjectGuid);
-            Assert.Empty(solution.ProjectsInOrder[1].Dependencies);
-            Assert.Null(solution.ProjectsInOrder[1].ParentProjectGuid);
-
-            Assert.Equal(@"ClassLibrary1\ClassLibrary1.csproj", solution.ProjectsInOrder[2].RelativePath);
-            Assert.Equal("{3A0EC360-A42A-417F-BDEF-619682CF6119}", solution.ProjectsInOrder[2].ProjectGuid);
-            Assert.Empty(solution.ProjectsInOrder[2].Dependencies);
-            Assert.Null(solution.ProjectsInOrder[2].ParentProjectGuid);
-
-            Assert.Equal(@"ClassLibrary2\ClassLibrary2.vbproj", solution.ProjectsInOrder[3].RelativePath);
-            Assert.Equal("{6DEF6DE8-FBF0-4240-B469-282DEE87899C}", solution.ProjectsInOrder[3].ProjectGuid);
-            Assert.Empty(solution.ProjectsInOrder[3].Dependencies);
-            Assert.Null(solution.ProjectsInOrder[3].ParentProjectGuid);
-        }
-
-        /// <summary>
-        /// Tests situation where there's a nonexistent project listed in the solution folders.  We should
-        /// error with a useful message.
-        /// </summary>
-        [Fact]
-        public void MissingNestedProject()
-        {
-            string solutionFileContents =
-                @"
-                Microsoft Visual Studio Solution File, Format Version 9.00
-                # Visual Studio 2005
-                Project('{2150E333-8FDC-42A3-9474-1A3956D46DE8}') = 'MySlnFolder', 'MySlnFolder', '{E0F97730-25D2-418A-A7BD-02CAFDC6E470}'
-                EndProject
-                Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'MyPhysicalFolder\ClassLibrary1\ClassLibrary1.csproj', '{A5EE8128-B08E-4533-86C5-E46714981680}'
-                EndProject
-                Global
-                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-                        Debug|Any CPU = Debug|Any CPU
-                        Release|Any CPU = Release|Any CPU
-                    EndGlobalSection
-                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
-                        {34E0D07D-CF8F-459D-9449-C4188D8C5564}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-                        {34E0D07D-CF8F-459D-9449-C4188D8C5564}.Debug|Any CPU.Build.0 = Debug|Any CPU
-                        {34E0D07D-CF8F-459D-9449-C4188D8C5564}.Release|Any CPU.ActiveCfg = Release|Any CPU
-                        {34E0D07D-CF8F-459D-9449-C4188D8C5564}.Release|Any CPU.Build.0 = Release|Any CPU
-                        {A5EE8128-B08E-4533-86C5-E46714981680}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-                        {A5EE8128-B08E-4533-86C5-E46714981680}.Debug|Any CPU.Build.0 = Debug|Any CPU
-                        {A5EE8128-B08E-4533-86C5-E46714981680}.Release|Any CPU.ActiveCfg = Release|Any CPU
-                        {A5EE8128-B08E-4533-86C5-E46714981680}.Release|Any CPU.Build.0 = Release|Any CPU
-                        {6DB98C35-FDCC-4818-B5D4-1F0A385FDFD4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-                        {6DB98C35-FDCC-4818-B5D4-1F0A385FDFD4}.Debug|Any CPU.Build.0 = Debug|Any CPU
-                        {6DB98C35-FDCC-4818-B5D4-1F0A385FDFD4}.Release|Any CPU.ActiveCfg = Release|Any CPU
-                        {6DB98C35-FDCC-4818-B5D4-1F0A385FDFD4}.Release|Any CPU.Build.0 = Release|Any CPU
-                    EndGlobalSection
-                    GlobalSection(SolutionProperties) = preSolution
-                        HideSolutionNode = FALSE
-                    EndGlobalSection
-                    GlobalSection(NestedProjects) = preSolution
-                        {A5EE8128-B08E-4533-86C5-E46714981680} = {E0F97730-25D2-418A-A7BD-02CAFDC6E470}
-                        {2AE8D6C4-FB43-430C-8AEB-15E5EEDAAE4B} = {E0F97730-25D2-418A-A7BD-02CAFDC6E470}
-                    EndGlobalSection
-                EndGlobal
-                ";
-
-            try
+            if (!convertToSlnx)
             {
-                ParseSolutionHelper(solutionFileContents);
+                Assert.Equal("{E0F97730-25D2-418A-A7BD-02CAFDC6E470}", myPhysicalFolderClassLibrary1.ParentProjectGuid);
+                Assert.Equal("{2AE8D6C4-FB43-430C-8AEB-15E5EEDAAE4B}", classLibrary2.ParentProjectGuid);
             }
-            catch (InvalidProjectFileException e)
+            else
             {
-                Assert.Equal("MSB5023", e.ErrorCode);
-                Assert.Contains("{2AE8D6C4-FB43-430C-8AEB-15E5EEDAAE4B}", e.Message);
-                return;
+                // try at least assert not null
+                Assert.NotNull(myPhysicalFolderClassLibrary1.ParentProjectGuid);
+                Assert.NotNull(classLibrary2.ParentProjectGuid);
             }
-
-            // Should not get here
-            Assert.Fail();
         }
 
         /// <summary>
@@ -711,19 +359,19 @@ public void SolutionDependencies(bool convertToSlnx)
             var classLibrary2 = solution.ProjectsInOrder.First(p => p.ProjectName == "ClassLibrary2");
             var classLibrary3 = solution.ProjectsInOrder.First(p => p.ProjectName == "ClassLibrary3");
 
-            Assert.Equal(ConvertToUnixPathIfNeeded("ClassLibrary1\\ClassLibrary1.csproj", convertToSlnx), classLibrary1.RelativePath);
+            Assert.Equal(ConvertToUnixPathIfNeeded("ClassLibrary1\\ClassLibrary1.csproj"), classLibrary1.RelativePath);
             Assert.Single(classLibrary1.Dependencies);
             Assert.Equal(classLibrary3.ProjectGuid, classLibrary1.Dependencies[0]);
             Assert.Null(solution.ProjectsInOrder[0].ParentProjectGuid);
 
-            Assert.Equal(ConvertToUnixPathIfNeeded("ClassLibrary2\\ClassLibrary2.csproj", convertToSlnx), classLibrary2.RelativePath);
+            Assert.Equal(ConvertToUnixPathIfNeeded("ClassLibrary2\\ClassLibrary2.csproj"), classLibrary2.RelativePath);
             Assert.Equal(2, classLibrary2.Dependencies.Count);
             // When converting to SLNX, the projects dependencies order is not preserved.
             Assert.Contains(classLibrary3.ProjectGuid, classLibrary2.Dependencies);
             Assert.Contains(classLibrary1.ProjectGuid, classLibrary2.Dependencies);
             Assert.Null(solution.ProjectsInOrder[1].ParentProjectGuid);
 
-            Assert.Equal(ConvertToUnixPathIfNeeded("ClassLibrary3\\ClassLibrary3.csproj", convertToSlnx), solution.ProjectsInOrder[2].RelativePath);
+            Assert.Equal(ConvertToUnixPathIfNeeded("ClassLibrary3\\ClassLibrary3.csproj"), solution.ProjectsInOrder[2].RelativePath);
             Assert.Empty(solution.ProjectsInOrder[2].Dependencies);
             Assert.Null(solution.ProjectsInOrder[2].ParentProjectGuid);
         }
@@ -867,85 +515,6 @@ public void ParseSolutionConfigurationsNoMixedPlatform(bool convertToSlnx)
             Assert.Equal("Any CPU", solution.GetDefaultPlatformName()); // "Default solution platform"
         }
 
-        /// <summary>
-        /// Test some invalid cases for solution configuration parsing.
-        /// There can be only one '=' character in a sln cfg entry, separating two identical names
-        /// </summary>
-        [Fact]
-        public void ParseInvalidSolutionConfigurations1()
-        {
-            Assert.Throws<InvalidProjectFileException>(() =>
-            {
-                string solutionFileContents =
-                    @"
-                Microsoft Visual Studio Solution File, Format Version 9.00
-                # Visual Studio 2005
-                Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'ClassLibrary1\ClassLibrary1.csproj', '{6185CC21-BE89-448A-B3C0-D1C27112E595}'
-                EndProject
-                Global
-                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-                        Debug|Any=CPU = Debug|Any=CPU
-                        Release|Any CPU = Release|Any CPU
-                    EndGlobalSection
-                EndGlobal
-                ";
-
-                ParseSolutionHelper(solutionFileContents);
-            });
-        }
-        /// <summary>
-        /// Test some invalid cases for solution configuration parsing
-        /// There can be only one '=' character in a sln cfg entry, separating two identical names
-        /// </summary>
-        [Fact]
-        public void ParseInvalidSolutionConfigurations2()
-        {
-            Assert.Throws<InvalidProjectFileException>(() =>
-            {
-                string solutionFileContents =
-                    @"
-                Microsoft Visual Studio Solution File, Format Version 9.00
-                # Visual Studio 2005
-                Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'ClassLibrary1\ClassLibrary1.csproj', '{6185CC21-BE89-448A-B3C0-D1C27112E595}'
-                EndProject
-                Global
-                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-                        Debug|Any CPU = Something|Else
-                        Release|Any CPU = Release|Any CPU
-                    EndGlobalSection
-                EndGlobal
-                ";
-
-                ParseSolutionHelper(solutionFileContents);
-            });
-        }
-        /// <summary>
-        /// Test some invalid cases for solution configuration parsing
-        /// Solution configurations must include the platform part
-        /// </summary>
-        [Fact]
-        public void ParseInvalidSolutionConfigurations3()
-        {
-            Assert.Throws<InvalidProjectFileException>(() =>
-            {
-                string solutionFileContents =
-                    @"
-                Microsoft Visual Studio Solution File, Format Version 9.00
-                # Visual Studio 2005
-                Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'ClassLibrary1\ClassLibrary1.csproj', '{6185CC21-BE89-448A-B3C0-D1C27112E595}'
-                EndProject
-                Global
-                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-                        Debug = Debug
-                        Release|Any CPU = Release|Any CPU
-                    EndGlobalSection
-                EndGlobal
-                ";
-
-                ParseSolutionHelper(solutionFileContents);
-            });
-        }
-
         /// <summary>
         /// Make sure the project configurations in solution configurations get parsed correctly
         /// for a simple mixed C#/VC solution
@@ -1046,69 +615,10 @@ public void ParseProjectConfigurationsInSolutionConfigurations1(bool convertToSl
             Assert.True(vcProject.ProjectConfigurations["Release|Win32"].IncludeInBuild);
         }
 
-        /// <summary>
-        /// Make sure the project configurations in solution configurations get parsed correctly
-        /// for a more tricky solution
-        /// </summary>
-        [Fact]
-        public void ParseProjectConfigurationsInSolutionConfigurations2()
-        {
-            string solutionFileContents =
-                @"
-                Microsoft Visual Studio Solution File, Format Version 9.00
-                # Visual Studio 2005
-                Project('{E24C65DC-7377-472B-9ABA-BC803B73C61A}') = 'C:\solutions\WebSite1\', '..\WebSite1\', '{E8E75132-67E4-4D6F-9CAE-8DA4C883F418}'
-                EndProject
-                Project('{E24C65DC-7377-472B-9ABA-BC803B73C61A}') = 'C:\solutions\WebSite2\', '..\WebSite2\', '{E8E75132-67E4-4D6F-9CAE-8DA4C883F419}'
-                EndProject
-                Project('{2150E333-8FDC-42A3-9474-1A3956D46DE8}') = 'NewFolder1', 'NewFolder1', '{54D20FFE-84BE-4066-A51E-B25D040A4235}'
-                EndProject
-                Project('{2150E333-8FDC-42A3-9474-1A3956D46DE8}') = 'NewFolder2', 'NewFolder2', '{D2633E4D-46FF-4C4E-8340-4BC7CDF78615}'
-                EndProject
-                Project('{8BC9CEB9-8B4A-11D0-8D11-00A0C91BC942}') = 'MSBuild.exe', '..\..\dd\binaries.x86dbg\bin\i386\MSBuild.exe', '{25FD9E7C-F37E-48E0-9A7C-607FE4AACCC0}'
-                EndProject
-                Global
-                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-                        Debug|.NET = Debug|.NET
-                    EndGlobalSection
-                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
-                        {E8E75132-67E4-4D6F-9CAE-8DA4C883F418}.Debug|.NET.ActiveCfg = Debug|.NET
-                        {E8E75132-67E4-4D6F-9CAE-8DA4C883F418}.Debug|.NET.Build.0 = Debug|.NET
-                        {25FD9E7C-F37E-48E0-9A7C-607FE4AACCC0}.Debug|.NET.ActiveCfg = Debug
-                    EndGlobalSection
-                    GlobalSection(SolutionProperties) = preSolution
-                        HideSolutionNode = FALSE
-                    EndGlobalSection
-                    GlobalSection(NestedProjects) = preSolution
-                        {25FD9E7C-F37E-48E0-9A7C-607FE4AACCC0} = {D2633E4D-46FF-4C4E-8340-4BC7CDF78615}
-                    EndGlobalSection
-                EndGlobal
-                ";
-
-            SolutionFile solution = ParseSolutionHelper(solutionFileContents);
-
-            ProjectInSolution webProject = (ProjectInSolution)solution.ProjectsByGuid["{E8E75132-67E4-4D6F-9CAE-8DA4C883F418}"];
-            ProjectInSolution exeProject = (ProjectInSolution)solution.ProjectsByGuid["{25FD9E7C-F37E-48E0-9A7C-607FE4AACCC0}"];
-            ProjectInSolution missingWebProject = (ProjectInSolution)solution.ProjectsByGuid["{E8E75132-67E4-4D6F-9CAE-8DA4C883F419}"];
-
-            Assert.Single(webProject.ProjectConfigurations);
-
-            Assert.Equal("Debug|.NET", webProject.ProjectConfigurations["Debug|.NET"].FullName);
-            Assert.True(webProject.ProjectConfigurations["Debug|.NET"].IncludeInBuild);
-
-            Assert.Single(exeProject.ProjectConfigurations);
-
-            Assert.Equal("Debug", exeProject.ProjectConfigurations["Debug|.NET"].FullName);
-            Assert.False(exeProject.ProjectConfigurations["Debug|.NET"].IncludeInBuild);
-
-            Assert.Empty(missingWebProject.ProjectConfigurations);
-
-            Assert.Equal("Debug", solution.GetDefaultConfigurationName()); // "Default solution configuration"
-            Assert.Equal(".NET", solution.GetDefaultPlatformName()); // "Default solution platform"
-        }
-
-        [Fact]
-        public void ParseProjectConfigurationsInSolutionConfigurationsSlnx()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void ParseProjectConfigurationsInSolutionConfigurations2(bool convertToSlnx)
         {
             string solutionFileContents =
                 """
@@ -1144,7 +654,7 @@ public void ParseProjectConfigurationsInSolutionConfigurationsSlnx()
                 EndGlobal
                 """;
 
-            SolutionFile solution = ParseSolutionHelper(solutionFileContents, true);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, convertToSlnx);
 
             ProjectInSolution winFormsApp1 = solution.ProjectsInOrder.First(p => p.ProjectName == "WinFormsApp1");
             ProjectInSolution classLibrary1 = solution.ProjectsInOrder.First(p => p.ProjectName == "ClassLibrary1");
@@ -1166,59 +676,6 @@ public void ParseProjectConfigurationsInSolutionConfigurationsSlnx()
             Assert.False(classLibrary1.ProjectConfigurations["Release|Any CPU"].IncludeInBuild);
         }
 
-        /// <summary>
-        /// Parse solution file with comments
-        /// </summary>
-        [Fact]
-        public void ParseSolutionWithComments()
-        {
-            const string solutionFileContent = @"
-                    Microsoft Visual Studio Solution File, Format Version 12.00
-                    # Visual Studio Version 16
-                    VisualStudioVersion = 16.0.29123.89
-                    MinimumVisualStudioVersion = 10.0.40219.1
-                    Project('{9A19103F-16F7-4668-BE54-9A1E7A4F7556}') = 'SlnCommentTest', 'SlnCommentTest.csproj', '{00000000-0000-0000-FFFF-FFFFFFFFFFFF}'
-                    EndProject
-                    Project('{2150E333-8FDC-42A3-9474-1A3956D46DE8}') = 'Solution Items', 'Solution Items', '{054DED3B-B890-4652-B449-839F581E5D86}'
-	                    ProjectSection(SolutionItems) = preProject
-		                    SlnFile.txt = SlnFile.txt
-	                    EndProjectSection
-                    EndProject
-                    Global
-	                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		                    Debug|Any CPU = Debug|Any CPU
-		                    Release|Any CPU = Release|Any CPU
-	                    EndGlobalSection
-	                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		                    {00000000-0000-0000-FFFF-FFFFFFFFFFFF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		                    {00000000-0000-0000-FFFF-FFFFFFFFFFFF}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		                    {00000000-0000-0000-FFFF-FFFFFFFFFFFF}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		                    {00000000-0000-0000-FFFF-FFFFFFFFFFFF}.Release|Any CPU.Build.0 = Release|Any CPU
-	                    EndGlobalSection
-	                    GlobalSection(SolutionProperties) = preSolution
-		                    HideSolutionNode = FALSE
-	                    EndGlobalSection
-	                    GlobalSection(ExtensibilityGlobals) = postSolution
-		                    SolutionGuid = {FFFFFFFF-FFFF-FFFF-0000-000000000000}
-	                    EndGlobalSection
-                    EndGlobal
-                    ";
-
-            StringBuilder stringBuilder = new StringBuilder();
-
-            // Put comment between all lines
-            const string comment = "\t# comment";
-            string[] lines = solutionFileContent.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
-            for (int i = 0; i < lines.Length; i++)
-            {
-                stringBuilder.AppendLine(comment);
-                stringBuilder.AppendLine(lines[i]);
-            }
-            stringBuilder.AppendLine(comment);
-
-            Should.NotThrow(() => ParseSolutionHelper(stringBuilder.ToString()));
-        }
-
         /// <summary>
         /// Helper method to create a SolutionFile object, and call it to parse the SLN file
         /// represented by the string contents passed in. Optionally can convert the SLN to SLNX and then parse the solution.
@@ -1246,11 +703,10 @@ private static string ConvertToSlnx(string slnPath)
             return slnxPath;
         }
 
-        private static string ConvertToUnixPathIfNeeded(string path, bool isConvertedToSlnx)
+        private static string ConvertToUnixPathIfNeeded(string path)
         {
             // In the new parser, ProjectModel.FilePath is converted to Unix-style.
-            // we are using the new parser only for slnx files.
-            return !NativeMethodsShared.IsWindows && isConvertedToSlnx ? path.Replace('\\', '/') : path;
+            return !NativeMethodsShared.IsWindows ? path.Replace('\\', '/') : path;
         }
     }
 }
diff --git a/src/Build.UnitTests/Construction/SolutionFile_Tests.cs b/src/Build.UnitTests/Construction/SolutionFile_OldParser_Tests.cs
similarity index 95%
rename from src/Build.UnitTests/Construction/SolutionFile_Tests.cs
rename to src/Build.UnitTests/Construction/SolutionFile_OldParser_Tests.cs
index 79bb93a4703..ab51906b222 100644
--- a/src/Build.UnitTests/Construction/SolutionFile_Tests.cs
+++ b/src/Build.UnitTests/Construction/SolutionFile_OldParser_Tests.cs
@@ -5,6 +5,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using System.IO;
+using System.Text;
 using Microsoft.Build.Construction;
 using Microsoft.Build.Exceptions;
 using Microsoft.Build.Shared;
@@ -16,11 +17,11 @@
 
 namespace Microsoft.Build.UnitTests.Construction
 {
-    public class SolutionFile_Tests
+    public class SolutionFile_OldParser_Tests
     {
         public ITestOutputHelper TestOutputHelper { get; }
 
-        public SolutionFile_Tests(ITestOutputHelper testOutputHelper)
+        public SolutionFile_OldParser_Tests(ITestOutputHelper testOutputHelper)
         {
             TestOutputHelper = testOutputHelper;
         }
@@ -104,6 +105,42 @@ public void ParseFirstProjectLineWithDifferentSpacing()
             proj.ProjectGuid.ShouldBe("Unique name-GUID");
         }
 
+        /// <summary>
+        /// A slightly more complicated test where there is some different whitespace.
+        /// </summary>
+        [Fact]
+        public void ParseSolutionWithDifferentSpacing()
+        {
+            string solutionFileContents =
+                @"
+                Microsoft Visual Studio Solution File, Format Version 9.00
+                # Visual Studio 2005
+                Project(' { Project GUID} ')  = ' Project name ',  ' Relative path to project file '    , ' {0ABED153-9451-483C-8140-9E8D7306B216} '
+                EndProject
+                Global
+                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                        Debug|AnyCPU = Debug|AnyCPU
+                        Release|AnyCPU = Release|AnyCPU
+                    EndGlobalSection
+                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.ActiveCfg = Debug|AnyCPU
+                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.Build.0 = Debug|AnyCPU
+                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.ActiveCfg = Release|AnyCPU
+                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.Build.0 = Release|AnyCPU
+                    EndGlobalSection
+                    GlobalSection(SolutionProperties) = preSolution
+                        HideSolutionNode = FALSE
+                    EndGlobalSection
+                EndGlobal
+                ";
+
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents);
+
+            Assert.Equal("Project name", solution.ProjectsInOrder[0].ProjectName);
+            Assert.Equal("Relative path to project file", solution.ProjectsInOrder[0].RelativePath);
+            Assert.Equal("{0ABED153-9451-483C-8140-9E8D7306B216}", solution.ProjectsInOrder[0].ProjectGuid);
+        }
+
         /// <summary>
         /// First project line with an empty project name.  This is somewhat malformed, but we should
         /// still behave reasonably instead of crashing.
@@ -687,6 +724,43 @@ public void ParseFirstProjectLineWhereProjectNameHasSpecialCharacters()
             proj.ProjectGuid.ShouldBe("Unique name-GUID");
         }
 
+        /// <summary>
+        /// Test some characters that are valid in a file name but that also could be
+        /// considered a delimiter by a parser. Does quoting work for special characters?
+        /// </summary>
+        [Fact]
+        public void ParseSolutionWhereProjectNameHasSpecialCharacters()
+        {
+            string solutionFileContents =
+                           @"
+                Microsoft Visual Studio Solution File, Format Version 9.00
+                # Visual Studio 2005
+                Project('{Project GUID}')  = 'MyProject,(=IsGreat)',  'Relative path to project file'    , '{0ABED153-9451-483C-8140-9E8D7306B216}'
+                EndProject
+                Global
+                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                        Debug|AnyCPU = Debug|AnyCPU
+                        Release|AnyCPU = Release|AnyCPU
+                    EndGlobalSection
+                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.ActiveCfg = Debug|AnyCPU
+                        {0ABED153-9451-483C-8140-9E8D7306B216}.Debug|AnyCPU.Build.0 = Debug|AnyCPU
+                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.ActiveCfg = Release|AnyCPU
+                        {0ABED153-9451-483C-8140-9E8D7306B216}.Release|AnyCPU.Build.0 = Release|AnyCPU
+                    EndGlobalSection
+                    GlobalSection(SolutionProperties) = preSolution
+                        HideSolutionNode = FALSE
+                    EndGlobalSection
+                EndGlobal
+                ";
+
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents);
+
+            Assert.Equal("MyProject,(=IsGreat)", solution.ProjectsInOrder[0].ProjectName);
+            Assert.Equal("Relative path to project file", solution.ProjectsInOrder[0].RelativePath);
+            Assert.Equal("{0ABED153-9451-483C-8140-9E8D7306B216}", solution.ProjectsInOrder[0].ProjectGuid);
+        }
+
         /// <summary>
         /// Test some characters that are valid in a file name but that also could be
         /// considered a delimiter by a parser. Does quoting work for special characters?
@@ -2355,5 +2429,58 @@ public void ParseSolutionWithParentedPaths()
             solution.ProjectsInOrder[0].AbsolutePath.ShouldBe(Path.GetFullPath(Path.Combine(Path.GetDirectoryName(solution.FullPath)!, expectedRelativePath)));
             solution.ProjectsInOrder[0].ProjectGuid.ShouldBe("{0ABED153-9451-483C-8140-9E8D7306B216}");
         }
+
+        /// <summary>
+        /// Parse solution file with comments
+        /// </summary>
+        [Fact]
+        public void ParseSolutionWithComments()
+        {
+            const string solutionFileContent = @"
+                    Microsoft Visual Studio Solution File, Format Version 12.00
+                    # Visual Studio Version 16
+                    VisualStudioVersion = 16.0.29123.89
+                    MinimumVisualStudioVersion = 10.0.40219.1
+                    Project('{9A19103F-16F7-4668-BE54-9A1E7A4F7556}') = 'SlnCommentTest', 'SlnCommentTest.csproj', '{00000000-0000-0000-FFFF-FFFFFFFFFFFF}'
+                    EndProject
+                    Project('{2150E333-8FDC-42A3-9474-1A3956D46DE8}') = 'Solution Items', 'Solution Items', '{054DED3B-B890-4652-B449-839F581E5D86}'
+	                    ProjectSection(SolutionItems) = preProject
+		                    SlnFile.txt = SlnFile.txt
+	                    EndProjectSection
+                    EndProject
+                    Global
+	                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		                    Debug|Any CPU = Debug|Any CPU
+		                    Release|Any CPU = Release|Any CPU
+	                    EndGlobalSection
+	                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		                    {00000000-0000-0000-FFFF-FFFFFFFFFFFF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		                    {00000000-0000-0000-FFFF-FFFFFFFFFFFF}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		                    {00000000-0000-0000-FFFF-FFFFFFFFFFFF}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		                    {00000000-0000-0000-FFFF-FFFFFFFFFFFF}.Release|Any CPU.Build.0 = Release|Any CPU
+	                    EndGlobalSection
+	                    GlobalSection(SolutionProperties) = preSolution
+		                    HideSolutionNode = FALSE
+	                    EndGlobalSection
+	                    GlobalSection(ExtensibilityGlobals) = postSolution
+		                    SolutionGuid = {FFFFFFFF-FFFF-FFFF-0000-000000000000}
+	                    EndGlobalSection
+                    EndGlobal
+                    ";
+
+            StringBuilder stringBuilder = new StringBuilder();
+
+            // Put comment between all lines
+            const string comment = "\t# comment";
+            string[] lines = solutionFileContent.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
+            for (int i = 0; i < lines.Length; i++)
+            {
+                stringBuilder.AppendLine(comment);
+                stringBuilder.AppendLine(lines[i]);
+            }
+            stringBuilder.AppendLine(comment);
+
+            Should.NotThrow(() => ParseSolutionHelper(stringBuilder.ToString()));
+        }
     }
 }
diff --git a/src/Build.UnitTests/Construction/SolutionFilter_Tests.cs b/src/Build.UnitTests/Construction/SolutionFilter_Tests.cs
index e173c47c640..1b988d17b0c 100644
--- a/src/Build.UnitTests/Construction/SolutionFilter_Tests.cs
+++ b/src/Build.UnitTests/Construction/SolutionFilter_Tests.cs
@@ -71,14 +71,14 @@ public void SolutionFilterFiltersProjects(bool graphBuild)
                     ");
                 // Slashes here (and in the .slnf) are hardcoded as backslashes intentionally to support the common case.
                 TransientTestFile solutionFile = testEnvironment.CreateFile(simpleProjectFolder, "SimpleProject.sln",
-                    @"
+                    """
                     Microsoft Visual Studio Solution File, Format Version 12.00
                     # Visual Studio Version 16
                     VisualStudioVersion = 16.0.29326.124
                     MinimumVisualStudioVersion = 10.0.40219.1
-                    Project(""{9A19103F-16F7-4668-BE54-9A1E7A4F7556}"") = ""SimpleProject"", ""SimpleProject\SimpleProject.csproj"", ""{79B5EBA6-5D27-4976-BC31-14422245A59A}""
+                    Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "SimpleProject", "SimpleProject\SimpleProject.csproj", "{79B5EBA6-5D27-4976-BC31-14422245A59A}"
                     EndProject
-                    Project(""{9A19103F-16F7-4668-BE54-9A1E7A4F7556}"") = ""ClassLibrary"", ""..\ClassLibrary\ClassLibrary\ClassLibrary.csproj"", ""{8EFCCA22-9D51-4268-90F7-A595E11FCB2D}""
+                    Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ClassLibrary", "..\ClassLibrary\ClassLibrary\ClassLibrary.csproj", "{8EFCCA22-9D51-4268-90F7-A595E11FCB2D}"
                     EndProject
                     Global
                         GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -106,7 +106,7 @@ public void SolutionFilterFiltersProjects(bool graphBuild)
                             SolutionGuid = {DE7234EC-0C4D-4070-B66A-DCF1B4F0CFEF}
                         EndGlobalSection
                     EndGlobal
-                ");
+                    """);
                 TransientTestFile filterFile = testEnvironment.CreateFile(folder, "solutionFilter.slnf",
                     @"
                 {
diff --git a/src/Build.UnitTests/Construction/SolutionProjectGenerator_Tests.cs b/src/Build.UnitTests/Construction/SolutionProjectGenerator_Tests.cs
index 8e28604557b..cd359a54c8b 100644
--- a/src/Build.UnitTests/Construction/SolutionProjectGenerator_Tests.cs
+++ b/src/Build.UnitTests/Construction/SolutionProjectGenerator_Tests.cs
@@ -38,6 +38,8 @@ public class SolutionProjectGenerator_Tests : IDisposable
 
         private static readonly BuildEventContext _buildEventContext = new BuildEventContext(0, 0, BuildEventContext.InvalidProjectContextId, 0);
 
+        private const string _longLineString = "a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-";
+
         public SolutionProjectGenerator_Tests(ITestOutputHelper output)
         {
             this.output = output;
@@ -65,12 +67,14 @@ public void SolutionProjectIgnoresDuplicateDefaultTargets(string name)
             using (TestEnvironment testEnvironment = TestEnvironment.Create())
             {
                 TransientTestFolder folder = testEnvironment.CreateFolder(createFolder: true);
-                TransientTestFile sln = testEnvironment.CreateFile(folder, "MySln.sln", @"Microsoft Visual Studio Solution File, Format Version 16.00");
+                TransientTestFile sln = testEnvironment.CreateFile(folder, "MySln.sln", "Microsoft Visual Studio Solution File, Format Version 12.00");
                 TransientTestFile targetsFile = testEnvironment.CreateFile(folder, name,
-                    @"<Project>
-                        <Target Name=""Build"" AfterTargets=""NonsenseTarget"">
+                      """
+                      <Project>
+                        <Target Name="Build" AfterTargets="NonsenseTarget">
                         </Target>
-                      </Project>");
+                      </Project>
+                      """);
                 ProjectInstance[] instances = SolutionProjectGenerator.Generate(SolutionFile.Parse(sln.Path), null, null, _buildEventContext, CreateMockLoggingService());
                 instances.ShouldHaveSingleItem();
                 instances[0].Targets["Build"].AfterTargets.ShouldBe(string.Empty);
@@ -87,33 +91,35 @@ public void BuildProjectAsTarget()
                 TransientTestFolder folder = testEnvironment.CreateFolder(createFolder: true);
                 TransientTestFolder classLibFolder = testEnvironment.CreateFolder(Path.Combine(folder.Path, "classlib"), createFolder: true);
                 TransientTestFile classLibrary = testEnvironment.CreateFile(classLibFolder, "classlib.csproj",
-                    @"<Project>
-                  <Target Name=""ClassLibraryTarget"">
-                      <Message Text=""ClassLibraryBuilt""/>
+                  """
+                  <Project>
+                  <Target Name="ClassLibraryTarget">
+                      <Message Text="ClassLibraryBuilt"/>
                   </Target>
                   </Project>
-                    ");
+                  """);
 
                 TransientTestFolder simpleProjectFolder = testEnvironment.CreateFolder(Path.Combine(folder.Path, "simpleProject"), createFolder: true);
                 TransientTestFile simpleProject = testEnvironment.CreateFile(simpleProjectFolder, "simpleProject.csproj",
-                    @"<Project>
-                  <Target Name=""SimpleProjectTarget"">
-                      <Message Text=""SimpleProjectBuilt""/>
+                  """
+                  <Project>
+                  <Target Name="SimpleProjectTarget">
+                      <Message Text="SimpleProjectBuilt"/>
                   </Target>
                   </Project>
-                    ");
+                  """);
 
                 TransientTestFile solutionFile = testEnvironment.CreateFile(folder, "testFolder.sln",
-                    @"
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
-VisualStudioVersion = 16.6.30114.105
-MinimumVisualStudioVersion = 10.0.40219.1
-Project(""{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"") = ""simpleProject"", ""simpleProject\simpleProject.csproj"", ""{AA52A05F-A9C0-4C89-9933-BF976A304C91}""
-EndProject
-Project(""{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"") = ""classlib"", ""classlib\classlib.csproj"", ""{80B8E6B8-E46D-4456-91B1-848FD35C4AB9}""
-EndProject
-                ");
+                    """
+                    Microsoft Visual Studio Solution File, Format Version 12.00
+                    # Visual Studio Version 16
+                    VisualStudioVersion = 16.6.30114.105
+                    MinimumVisualStudioVersion = 10.0.40219.1
+                    Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "simpleProject", "simpleProject\simpleProject.csproj", "{AA52A05F-A9C0-4C89-9933-BF976A304C91}"
+                    EndProject
+                    Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "classlib", "classlib\classlib.csproj", "{80B8E6B8-E46D-4456-91B1-848FD35C4AB9}"
+                    EndProject
+                    """);
                 RunnerUtilities.ExecMSBuild(solutionFile.Path + " /t:classlib", out bool success);
                 success.ShouldBeTrue();
             }
@@ -130,56 +136,58 @@ public void BuildProjectWithMultipleTargets()
                 TransientTestFolder folder = testEnvironment.CreateFolder(createFolder: true);
                 TransientTestFolder classLibFolder = testEnvironment.CreateFolder(Path.Combine(folder.Path, "classlib"), createFolder: true);
                 TransientTestFile classLibrary = testEnvironment.CreateFile(classLibFolder, "classlib.csproj",
-                    @"<Project>
-                  <Target Name=""Build"">
-                      <Message Text=""classlib.Build""/>
+                  """
+                  <Project>
+                  <Target Name="Build">
+                      <Message Text="classlib.Build"/>
                   </Target>
-                  <Target Name=""Clean"">
-                      <Message Text=""classlib.Clean""/>
+                  <Target Name="Clean">
+                      <Message Text="classlib.Clean"/>
                   </Target>
-                  <Target Name=""Custom"">
-                      <Message Text=""classlib.Custom""/>
+                  <Target Name="Custom">
+                      <Message Text="classlib.Custom"/>
                   </Target>
                   </Project>
-                    ");
+                  """);
 
                 TransientTestFolder simpleProjectFolder = testEnvironment.CreateFolder(Path.Combine(folder.Path, "simpleProject"), createFolder: true);
                 TransientTestFile simpleProject = testEnvironment.CreateFile(simpleProjectFolder, "simpleProject.csproj",
-                    @"<Project>
-                  <Target Name=""Build"">
-                      <Message Text=""simpleProject.Build""/>
+                  """
+                  <Project>
+                  <Target Name="Build">
+                      <Message Text="simpleProject.Build"/>
                   </Target>
-                  <Target Name=""Clean"">
-                      <Message Text=""simpleProject.Clean""/>
+                  <Target Name="Clean">
+                      <Message Text="simpleProject.Clean"/>
                   </Target>
-                  <Target Name=""Custom"">
-                      <Message Text=""simpleProject.Custom""/>
+                  <Target Name="Custom">
+                      <Message Text="simpleProject.Custom"/>
                   </Target>
                   </Project>
-                    ");
+                  """);
 
                 TransientTestFile solutionFile = testEnvironment.CreateFile(folder, "testFolder.sln",
-                    @"
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
-VisualStudioVersion = 16.6.30114.105
-MinimumVisualStudioVersion = 10.0.40219.1
-Project(""{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"") = ""simpleProject"", ""simpleProject\simpleProject.csproj"", ""{AA52A05F-A9C0-4C89-9933-BF976A304C91}""
-EndProject
-Project(""{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"") = ""classlib"", ""classlib\classlib.csproj"", ""{80B8E6B8-E46D-4456-91B1-848FD35C4AB9}""
-EndProject
-Global
-	GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		Debug|x86 = Debug|x86
-	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{AA52A05F-A9C0-4C89-9933-BF976A304C91}.Debug|x86.ActiveCfg = Debug|x86
-		{AA52A05F-A9C0-4C89-9933-BF976A304C91}.Debug|x86.Build.0 = Debug|x86
-		{80B8E6B8-E46D-4456-91B1-848FD35C4AB9}.Debug|x86.ActiveCfg = Debug|x86
-		{80B8E6B8-E46D-4456-91B1-848FD35C4AB9}.Debug|x86.Build.0 = Debug|x86
-	EndGlobalSection
-EndGlobal
-                ");
+                    """
+                    Microsoft Visual Studio Solution File, Format Version 12.00
+                    # Visual Studio Version 16
+                    VisualStudioVersion = 16.6.30114.105
+                    MinimumVisualStudioVersion = 10.0.40219.1
+                    Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "simpleProject", "simpleProject\simpleProject.csproj", "{AA52A05F-A9C0-4C89-9933-BF976A304C91}"
+                    EndProject
+                    Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "classlib", "classlib\classlib.csproj", "{80B8E6B8-E46D-4456-91B1-848FD35C4AB9}"
+                    EndProject
+                    Global
+                        GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                            Debug|x86 = Debug|x86
+                        EndGlobalSection
+                        GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                            {AA52A05F-A9C0-4C89-9933-BF976A304C91}.Debug|x86.ActiveCfg = Debug|x86
+                            {AA52A05F-A9C0-4C89-9933-BF976A304C91}.Debug|x86.Build.0 = Debug|x86
+                            {80B8E6B8-E46D-4456-91B1-848FD35C4AB9}.Debug|x86.ActiveCfg = Debug|x86
+                            {80B8E6B8-E46D-4456-91B1-848FD35C4AB9}.Debug|x86.Build.0 = Debug|x86
+                        EndGlobalSection
+                        EndGlobal
+                    """);
 
                 string output = RunnerUtilities.ExecMSBuild(solutionFile.Path + " /t:Clean;Build;Custom", out bool success);
                 success.ShouldBeTrue();
@@ -204,56 +212,58 @@ public void BuildProjectWithMultipleTargetsInParallel()
                 TransientTestFolder folder = testEnvironment.CreateFolder(createFolder: true);
                 TransientTestFolder classLibFolder = testEnvironment.CreateFolder(Path.Combine(folder.Path, "classlib"), createFolder: true);
                 TransientTestFile classLibrary = testEnvironment.CreateFile(classLibFolder, "classlib.csproj",
-                    @"<Project>
-                  <Target Name=""Build"">
-                      <Message Text=""classlib.Build""/>
+                  """
+                  <Project>
+                  <Target Name="Build">
+                      <Message Text="classlib.Build"/>
                   </Target>
-                  <Target Name=""Clean"">
-                      <Message Text=""classlib.Clean""/>
+                  <Target Name="Clean">
+                      <Message Text="classlib.Clean"/>
                   </Target>
-                  <Target Name=""Custom"">
-                      <Message Text=""classlib.Custom""/>
+                  <Target Name="Custom">
+                      <Message Text="classlib.Custom"/>
                   </Target>
                   </Project>
-                    ");
+                  """);
 
                 TransientTestFolder simpleProjectFolder = testEnvironment.CreateFolder(Path.Combine(folder.Path, "simpleProject"), createFolder: true);
                 TransientTestFile simpleProject = testEnvironment.CreateFile(simpleProjectFolder, "simpleProject.csproj",
-                    @"<Project>
-                  <Target Name=""Build"">
-                      <Message Text=""simpleProject.Build""/>
+                  """
+                  <Project>
+                  <Target Name="Build">
+                      <Message Text="simpleProject.Build"/>
                   </Target>
-                  <Target Name=""Clean"">
-                      <Message Text=""simpleProject.Clean""/>
+                  <Target Name="Clean">
+                      <Message Text="simpleProject.Clean"/>
                   </Target>
-                  <Target Name=""Custom"">
-                      <Message Text=""simpleProject.Custom""/>
+                  <Target Name="Custom">
+                      <Message Text="simpleProject.Custom"/>
                   </Target>
                   </Project>
-                    ");
+                  """);
 
                 TransientTestFile solutionFile = testEnvironment.CreateFile(folder, "testFolder.sln",
-                    @"
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
-VisualStudioVersion = 16.6.30114.105
-MinimumVisualStudioVersion = 10.0.40219.1
-Project(""{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"") = ""simpleProject"", ""simpleProject\simpleProject.csproj"", ""{AA52A05F-A9C0-4C89-9933-BF976A304C91}""
-EndProject
-Project(""{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"") = ""classlib"", ""classlib\classlib.csproj"", ""{80B8E6B8-E46D-4456-91B1-848FD35C4AB9}""
-EndProject
-Global
-	GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		Debug|x86 = Debug|x86
-	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{AA52A05F-A9C0-4C89-9933-BF976A304C91}.Debug|x86.ActiveCfg = Debug|x86
-		{AA52A05F-A9C0-4C89-9933-BF976A304C91}.Debug|x86.Build.0 = Debug|x86
-		{80B8E6B8-E46D-4456-91B1-848FD35C4AB9}.Debug|x86.ActiveCfg = Debug|x86
-		{80B8E6B8-E46D-4456-91B1-848FD35C4AB9}.Debug|x86.Build.0 = Debug|x86
-	EndGlobalSection
-EndGlobal
-                ");
+                    """
+                    Microsoft Visual Studio Solution File, Format Version 12.00
+                    # Visual Studio Version 16
+                    VisualStudioVersion = 16.6.30114.105
+                    MinimumVisualStudioVersion = 10.0.40219.1
+                    Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "simpleProject", "simpleProject\simpleProject.csproj", "{AA52A05F-A9C0-4C89-9933-BF976A304C91}"
+                    EndProject
+                    Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "classlib", "classlib\classlib.csproj", "{80B8E6B8-E46D-4456-91B1-848FD35C4AB9}"
+                    EndProject
+                    Global
+                        GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                            Debug|x86 = Debug|x86
+                        EndGlobalSection
+                        GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                            {AA52A05F-A9C0-4C89-9933-BF976A304C91}.Debug|x86.ActiveCfg = Debug|x86
+                            {AA52A05F-A9C0-4C89-9933-BF976A304C91}.Debug|x86.Build.0 = Debug|x86
+                            {80B8E6B8-E46D-4456-91B1-848FD35C4AB9}.Debug|x86.ActiveCfg = Debug|x86
+                            {80B8E6B8-E46D-4456-91B1-848FD35C4AB9}.Debug|x86.Build.0 = Debug|x86
+                        EndGlobalSection
+                    EndGlobal
+                    """);
 
                 try
                 {
@@ -331,10 +341,12 @@ public void AddNewErrorWarningMessageElement()
         /// Test to make sure we properly set the ToolsVersion attribute on the in-memory project based
         /// on the Solution File Format Version.
         /// </summary>
-        [Fact]
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
         [Trait("Category", "netcore-osx-failing")]
         [Trait("Category", "netcore-linux-failing")]
-        public void EmitToolsVersionAttributeToInMemoryProject9()
+        public void EmitToolsVersionAttributeToInMemoryProject9(bool useNewParser)
         {
             if (FrameworkLocationHelper.PathToDotNetFrameworkV35 == null)
             {
@@ -343,7 +355,7 @@ public void EmitToolsVersionAttributeToInMemoryProject9()
             }
 
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 Global
                     GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -353,9 +365,9 @@ public void EmitToolsVersionAttributeToInMemoryProject9()
                         Other|Win32 = Other|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, null, "3.5", _buildEventContext, CreateMockLoggingService());
 
@@ -366,10 +378,12 @@ public void EmitToolsVersionAttributeToInMemoryProject9()
         /// Test to make sure we properly set the ToolsVersion attribute on the in-memory project based
         /// on the Solution File Format Version.
         /// </summary>
-        [Fact]
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
         [Trait("Category", "netcore-osx-failing")]
         [Trait("Category", "netcore-linux-failing")]
-        public void EmitToolsVersionAttributeToInMemoryProject10()
+        public void EmitToolsVersionAttributeToInMemoryProject10(bool useNewParser)
         {
             if (FrameworkLocationHelper.PathToDotNetFrameworkV35 == null)
             {
@@ -378,7 +392,7 @@ public void EmitToolsVersionAttributeToInMemoryProject10()
             }
 
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 10.00
                 Global
                     GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -388,9 +402,9 @@ public void EmitToolsVersionAttributeToInMemoryProject10()
                         Other|Win32 = Other|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, null, "3.5", _buildEventContext, CreateMockLoggingService());
 
@@ -407,7 +421,7 @@ public void DefaultSubToolsetIfSolutionVersionSubToolsetDoesntExist()
             Environment.SetEnvironmentVariable("VisualStudioVersion", null);
 
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 10.00
                 Global
                     GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -417,9 +431,9 @@ public void DefaultSubToolsetIfSolutionVersionSubToolsetDoesntExist()
                         Other|Win32 = Other|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = SolutionFile_OldParser_Tests.ParseSolutionHelper(solutionFileContents);
 
             ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, null, null, _buildEventContext, CreateMockLoggingService());
 
@@ -443,13 +457,15 @@ public void DefaultSubToolsetIfSolutionVersionSubToolsetDoesntExist()
         /// Test to make sure that if the solution version corresponds to an existing sub-toolset version,
         /// barring other factors that might override, the sub-toolset will be based on the solution version.
         /// </summary>
-        [Fact]
-        public void SubToolsetSetBySolutionVersion()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void SubToolsetSetBySolutionVersion(bool useNewParser)
         {
             Environment.SetEnvironmentVariable("VisualStudioVersion", null);
 
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 12.00
                 Global
                     GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -459,9 +475,9 @@ public void SubToolsetSetBySolutionVersion()
                         Other|Win32 = Other|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, null, null, _buildEventContext, CreateMockLoggingService());
 
@@ -478,13 +494,15 @@ public void SubToolsetSetBySolutionVersion()
         /// <summary>
         /// Test to make sure that even if the solution version corresponds to an existing sub-toolset version,
         /// </summary>
-        [Fact]
-        public void SolutionBasedSubToolsetVersionOverriddenByEnvironment()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void SolutionBasedSubToolsetVersionOverriddenByEnvironment(bool useNewParser)
         {
             Environment.SetEnvironmentVariable("VisualStudioVersion", "ABC");
 
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 12.00
                 Global
                     GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -494,9 +512,9 @@ public void SolutionBasedSubToolsetVersionOverriddenByEnvironment()
                         Other|Win32 = Other|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, null, null, _buildEventContext, CreateMockLoggingService());
 
@@ -719,44 +737,45 @@ public void SolutionDoesntPassSubToolsetToChildProjects()
         /// Verify that we throw the appropriate error if the solution declares a dependency
         /// on a project that doesn't exist.
         /// </summary>
+        /// <remarks>This test would only work for the old parser. In the new parser the dependency is not added if it was not in the solution file.</remarks>
         [Fact]
         public void SolutionWithMissingDependencies()
         {
             Assert.Throws<InvalidProjectFileException>(() =>
             {
                 string solutionFileContents =
-                    @"
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 11
-Project(`{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}`) = `B`, `Project2\B.csproj`, `{881C1674-4ECA-451D-85B6-D7C59B7F16FA}`
-    ProjectSection(ProjectDependencies) = postProject
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167} = {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}
-    EndProjectSection
-EndProject
-Global
-    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-        Debug|Any CPU = Debug|Any CPU
-        Debug|x64 = Debug|x64
-        Release|Any CPU = Release|Any CPU
-        Release|x64 = Release|x64
-    EndGlobalSection
-    GlobalSection(ProjectConfigurationPlatforms) = preSolution
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.Build.0 = Debug|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|x64.ActiveCfg = Debug|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|x64.Build.0 = Debug|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|Any CPU.ActiveCfg = Release|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|Any CPU.Build.0 = Release|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|x64.ActiveCfg = Release|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|x64.Build.0 = Release|Any CPU
-    EndGlobalSection
-    GlobalSection(SolutionProperties) = preSolution
-        HideSolutionNode = FALSE
-    EndGlobalSection
-EndGlobal
-".Replace("`", "\"");
+                    """
+                    Microsoft Visual Studio Solution File, Format Version 12.00
+                    # Visual Studio 11
+                    Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "B", "Project2\B.csproj", "{881C1674-4ECA-451D-85B6-D7C59B7F16FA}"
+                        ProjectSection(ProjectDependencies) = postProject
+                            {4A727FF8-65F2-401E-95AD-7C8BBFBE3167} = {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}
+                        EndProjectSection
+                    EndProject
+                    Global
+                        GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                            Debug|Any CPU = Debug|Any CPU
+                            Debug|x64 = Debug|x64
+                            Release|Any CPU = Release|Any CPU
+                            Release|x64 = Release|x64
+                        EndGlobalSection
+                        GlobalSection(ProjectConfigurationPlatforms) = preSolution
+                            {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                            {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                            {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|x64.ActiveCfg = Debug|Any CPU
+                            {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|x64.Build.0 = Debug|Any CPU
+                            {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|Any CPU.ActiveCfg = Release|Any CPU
+                            {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|Any CPU.Build.0 = Release|Any CPU
+                            {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|x64.ActiveCfg = Release|Any CPU
+                            {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|x64.Build.0 = Release|Any CPU
+                        EndGlobalSection
+                        GlobalSection(SolutionProperties) = preSolution
+                            HideSolutionNode = FALSE
+                        EndGlobalSection
+                    EndGlobal
+                    """;
 
-                SolutionFile sp = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+                SolutionFile sp = SolutionFile_OldParser_Tests.ParseSolutionHelper(solutionFileContents);
                 ProjectInstance[] instances = SolutionProjectGenerator.Generate(sp, null, null, _buildEventContext, CreateMockLoggingService());
             });
         }
@@ -764,62 +783,64 @@ public void SolutionWithMissingDependencies()
         /// Blob should contain dependency info
         /// Here B depends on C
         /// </summary>
-        [Fact]
-        public void SolutionConfigurationWithDependencies()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void SolutionConfigurationWithDependencies(bool useNewParser)
         {
             string solutionFileContents =
-                @"
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 11
-Project(`{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}`) = `A`, `Project1\A.csproj`, `{786E302A-96CE-43DC-B640-D6B6CC9BF6C0}`
-EndProject
-Project(`{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}`) = `B`, `Project2\B.csproj`, `{881C1674-4ECA-451D-85B6-D7C59B7F16FA}`
-    ProjectSection(ProjectDependencies) = postProject
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167} = {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}
-    EndProjectSection
-EndProject
-Project(`{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}`) = `C`, `Project3\C.csproj`, `{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}`
-EndProject
-Global
-    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-        Debug|Any CPU = Debug|Any CPU
-        Debug|x64 = Debug|x64
-        Release|Any CPU = Release|Any CPU
-        Release|x64 = Release|x64
-    EndGlobalSection
-    GlobalSection(ProjectConfigurationPlatforms) = preSolution
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|Any CPU.Build.0 = Debug|Any CPU
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|x64.ActiveCfg = Debug|Any CPU
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|x64.Build.0 = Debug|Any CPU
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Release|Any CPU.ActiveCfg = Release|Any CPU
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Release|Any CPU.Build.0 = Release|Any CPU
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Release|x64.ActiveCfg = Release|Any CPU
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Release|x64.Build.0 = Release|Any CPU
-        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Debug|Any CPU.Build.0 = Debug|Any CPU
-        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Debug|x64.ActiveCfg = Debug|Any CPU
-        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Debug|x64.Build.0 = Debug|Any CPU
-        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Release|Any CPU.ActiveCfg = Release|Any CPU
-        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Release|Any CPU.Build.0 = Release|Any CPU
-        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Release|x64.ActiveCfg = Release|Any CPU
-        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Release|x64.Build.0 = Release|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.Build.0 = Debug|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|x64.ActiveCfg = Debug|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|x64.Build.0 = Debug|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|Any CPU.ActiveCfg = Release|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|Any CPU.Build.0 = Release|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|x64.ActiveCfg = Release|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|x64.Build.0 = Release|Any CPU
-    EndGlobalSection
-    GlobalSection(SolutionProperties) = preSolution
-        HideSolutionNode = FALSE
-    EndGlobalSection
-EndGlobal
-".Replace("`", "\"");
+                """
+                Microsoft Visual Studio Solution File, Format Version 12.00
+                # Visual Studio 11
+                Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "A", "Project1\A.csproj", "{786E302A-96CE-43DC-B640-D6B6CC9BF6C0}"
+                EndProject
+                Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "B", "Project2\B.csproj", "{881C1674-4ECA-451D-85B6-D7C59B7F16FA}"
+                    ProjectSection(ProjectDependencies) = postProject
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167} = {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}
+                    EndProjectSection
+                EndProject
+                Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "C", "Project3\C.csproj", "{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}"
+                EndProject
+                Global
+                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                        Debug|Any CPU = Debug|Any CPU
+                        Debug|x64 = Debug|x64
+                        Release|Any CPU = Release|Any CPU
+                        Release|x64 = Release|x64
+                    EndGlobalSection
+                    GlobalSection(ProjectConfigurationPlatforms) = preSolution
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|x64.ActiveCfg = Debug|Any CPU
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|x64.Build.0 = Debug|Any CPU
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Release|Any CPU.ActiveCfg = Release|Any CPU
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Release|Any CPU.Build.0 = Release|Any CPU
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Release|x64.ActiveCfg = Release|Any CPU
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Release|x64.Build.0 = Release|Any CPU
+                        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Debug|x64.ActiveCfg = Debug|Any CPU
+                        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Debug|x64.Build.0 = Debug|Any CPU
+                        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+                        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Release|Any CPU.Build.0 = Release|Any CPU
+                        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Release|x64.ActiveCfg = Release|Any CPU
+                        {786E302A-96CE-43DC-B640-D6B6CC9BF6C0}.Release|x64.Build.0 = Release|Any CPU
+                        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|x64.ActiveCfg = Debug|Any CPU
+                        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|x64.Build.0 = Debug|Any CPU
+                        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|Any CPU.ActiveCfg = Release|Any CPU
+                        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|Any CPU.Build.0 = Release|Any CPU
+                        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|x64.ActiveCfg = Release|Any CPU
+                        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Release|x64.Build.0 = Release|Any CPU
+                    EndGlobalSection
+                    GlobalSection(SolutionProperties) = preSolution
+                        HideSolutionNode = FALSE
+                    EndGlobalSection
+                EndGlobal
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectRootElement projectXml = ProjectRootElement.Create();
 
@@ -838,11 +859,14 @@ public void SolutionConfigurationWithDependencies()
             string solutionConfigurationContents = msbuildProject.GetPropertyValue("CurrentSolutionConfigurationContents");
 
             // Only the specified solution configuration is represented in THE BLOB: nothing for x64 in this case
-            string expected = $@"<SolutionConfiguration>
-  <ProjectConfiguration Project=`{{786E302A-96CE-43DC-B640-D6B6CC9BF6C0}}` AbsolutePath=`##temp##{Path.Combine("Project1", "A.csproj")}` BuildProjectInSolution=`True`>Debug|AnyCPU</ProjectConfiguration>
-  <ProjectConfiguration Project=`{{881C1674-4ECA-451D-85B6-D7C59B7F16FA}}` AbsolutePath=`##temp##{Path.Combine("Project2", "B.csproj")}` BuildProjectInSolution=`True`>Debug|AnyCPU<ProjectDependency Project=`{{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}}` /></ProjectConfiguration>
-  <ProjectConfiguration Project=`{{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}}` AbsolutePath=`##temp##{Path.Combine("Project3", "C.csproj")}` BuildProjectInSolution=`True`>Debug|AnyCPU</ProjectConfiguration>
-</SolutionConfiguration>".Replace("`", "\"").Replace("##temp##", FileUtilities.TempFileDirectory);
+            string expected =
+                $$"""
+                <SolutionConfiguration>
+                  <ProjectConfiguration Project="{786E302A-96CE-43DC-B640-D6B6CC9BF6C0}" AbsolutePath="##temp##{{Path.Combine("Project1", "A.csproj")}}" BuildProjectInSolution="True">Debug|AnyCPU</ProjectConfiguration>
+                  <ProjectConfiguration Project="{881C1674-4ECA-451D-85B6-D7C59B7F16FA}" AbsolutePath="##temp##{{Path.Combine("Project2", "B.csproj")}}" BuildProjectInSolution="True">Debug|AnyCPU<ProjectDependency Project="{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}" /></ProjectConfiguration>
+                  <ProjectConfiguration Project="{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}" AbsolutePath="##temp##{{Path.Combine("Project3", "C.csproj")}}" BuildProjectInSolution="True">Debug|AnyCPU</ProjectConfiguration>
+                </SolutionConfiguration>
+                """.Replace("##temp##", FileUtilities.TempFileDirectory);
 
             Helpers.VerifyAssertLineByLine(expected, solutionConfigurationContents);
         }
@@ -860,19 +884,19 @@ public void SolutionGeneratingMetaproj()
                 TransientTestFile proj2 = env.CreateFile("B.csproj", @"<Project><Target Name=""Printer""><Message Importance=""high"" Text=""print string"" /></Target></Project>");
                 TransientTestFile proj3 = env.CreateFile("C.csproj", @"<Project><Target Name=""Printer""><Message Importance=""high"" Text=""print string"" /></Target></Project>");
                 TransientTestFile proj = env.CreateFile("mysln.sln",
-                @$"
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 11
-Project(`{"{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"}`) = `A`, `{proj1.Path}`, `{"{786E302A-96CE-43DC-B640-D6B6CC9BF6C0}"}`
-EndProject
-Project(`{"{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"}`) = `B`, `{proj2.Path}`, `{"{881C1674-4ECA-451D-85B6-D7C59B7F16FA}"}`
-    ProjectSection(ProjectDependencies) = postProject
-        {"{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}"} = {"{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}"}
-    EndProjectSection
-EndProject
-Project(`{"{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"}`) = `C`, `{proj3.Path}`, `{"{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}"}`
-EndProject
-".Replace("`", "\""));
+                    $$"""
+                    Microsoft Visual Studio Solution File, Format Version 12.00
+                    # Visual Studio 11
+                    Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "A", "{{proj1.Path}}", "{786E302A-96CE-43DC-B640-D6B6CC9BF6C0}"
+                    EndProject
+                    Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "B", "{{proj2.Path}}", "{881C1674-4ECA-451D-85B6-D7C59B7F16FA}"
+                        ProjectSection(ProjectDependencies) = postProject
+                            {"{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}"} = {"{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}"}
+                        EndProjectSection
+                    EndProject
+                    Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "C", "{{proj3.Path}}", "{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}"
+                    EndProject
+                    """);
                 RunnerUtilities.ExecMSBuild("\"" + proj.Path + "\"", out bool successfulExit);
                 successfulExit.ShouldBeTrue();
             }
@@ -890,37 +914,37 @@ public void SolutionConfigurationWithDependenciesRelaysItsOutputs()
         {
             #region Large strings representing solution & projects
             const string solutionFileContents =
-                @"
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 11
-Project(`{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}`) = `B`, `B.csproj`, `{881C1674-4ECA-451D-85B6-D7C59B7F16FA}`
-    ProjectSection(ProjectDependencies) = postProject
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167} = {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}
-    EndProjectSection
-EndProject
-Project(`{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}`) = `C`, `C.csproj`, `{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}`
-EndProject
-Project(`{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}`) = `D`, `D.csproj`, `{B6E7E06F-FC0B-48F1-911A-55E0E1566F00}`
-EndProject
-Global
-    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-        Debug|Any CPU = Debug|Any CPU
-    EndGlobalSection
-    GlobalSection(ProjectConfigurationPlatforms) = preSolution
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|Any CPU.Build.0 = Debug|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.Build.0 = Debug|Any CPU
-        {B6E7E06F-FC0B-48F1-911A-55E0E1566F00}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-        {B6E7E06F-FC0B-48F1-911A-55E0E1566F00}.Debug|Any CPU.Build.0 = Debug|Any CPU
-    EndGlobalSection
-    GlobalSection(SolutionProperties) = preSolution
-        HideSolutionNode = FALSE
-    EndGlobalSection
-EndGlobal
-";
+                """
+                Microsoft Visual Studio Solution File, Format Version 12.00
+                # Visual Studio 11
+                Project(`{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}`) = `B`, `B.csproj`, `{881C1674-4ECA-451D-85B6-D7C59B7F16FA}`
+                    ProjectSection(ProjectDependencies) = postProject
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167} = {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}
+                    EndProjectSection
+                EndProject
+                Project(`{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}`) = `C`, `C.csproj`, `{4A727FF8-65F2-401E-95AD-7C8BBFBE3167}`
+                EndProject
+                Project(`{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}`) = `D`, `D.csproj`, `{B6E7E06F-FC0B-48F1-911A-55E0E1566F00}`
+                EndProject
+                Global
+                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                        Debug|Any CPU = Debug|Any CPU
+                    EndGlobalSection
+                    GlobalSection(ProjectConfigurationPlatforms) = preSolution
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {4A727FF8-65F2-401E-95AD-7C8BBFBE3167}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {881C1674-4ECA-451D-85B6-D7C59B7F16FA}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                        {B6E7E06F-FC0B-48F1-911A-55E0E1566F00}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {B6E7E06F-FC0B-48F1-911A-55E0E1566F00}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                    EndGlobalSection
+                    GlobalSection(SolutionProperties) = preSolution
+                        HideSolutionNode = FALSE
+                    EndGlobalSection
+                EndGlobal
+                """;
             const string projectBravoFileContents =
-                    @"
+                    """
                         <Project ToolsVersion='msbuilddefaulttoolsversion' DefaultTargets='Build' xmlns='msbuildnamespace'>
                             <Target Name='Build' Outputs='@(ComputedQuestion)'>
                                 <ItemGroup>
@@ -934,9 +958,9 @@ public void SolutionConfigurationWithDependenciesRelaysItsOutputs()
                                 </ProjectReference>
                             </ItemGroup>
                         </Project>
-                    ";
+                    """;
             const string projectCharlieFileContents =
-                    @"
+                    """
                         <Project ToolsVersion='msbuilddefaulttoolsversion' DefaultTargets='Build' xmlns='msbuildnamespace'>
                             <Target Name='Build' Outputs='@(ComputedAnswer)'>
                                 <ItemGroup>
@@ -944,9 +968,9 @@ public void SolutionConfigurationWithDependenciesRelaysItsOutputs()
                                 </ItemGroup>
                             </Target>
                         </Project>
-                    ";
+                    """;
             const string projectDeltaFileContents =
-                    @"
+                    """
                         <Project ToolsVersion='msbuilddefaulttoolsversion' DefaultTargets='Build' xmlns='msbuildnamespace'>
                             <PropertyGroup>
                                 <ProjectGuid>{B6E7E06F-FC0B-48F1-911A-55E0E1566F00}</ProjectGuid>
@@ -957,60 +981,62 @@ public void SolutionConfigurationWithDependenciesRelaysItsOutputs()
                                 </ItemGroup>
                             </Target>
                         </Project>
-                    ";
-            const string automaticProjectFileContents = @"
-<Project ToolsVersion='msbuilddefaulttoolsversion' DefaultTargets='compile' xmlns='msbuildnamespace'>
-    <Target Name='compile'>
-        <!-- Build projects to get a baseline for their output -->
-        <MSBuild Projects='B.csproj' Targets='Build'>
-            <Output
-                TaskParameter='TargetOutputs'
-                ItemName='BravoProjectOutputs' />
-        </MSBuild>
-        <Message Importance='high' Text='BravoProjectOutputs: @(BravoProjectOutputs)' />
-
-        <MSBuild Projects='C.csproj' Targets='Build'>
-            <Output
-                TaskParameter='TargetOutputs'
-                ItemName='CharlieProjectOutputs' />
-        </MSBuild>
-        <Message Importance='high' Text='CharlieProjectOutputs: @(CharlieProjectOutputs)' />
-
-        <MSBuild Projects='D.csproj' Targets='Build'>
-            <Output
-                TaskParameter='TargetOutputs'
-                ItemName='DeltaProjectOutputs' />
-        </MSBuild>
-        <Message Importance='high' Text='DeltaProjectOutputs: @(DeltaProjectOutputs)' />
-
-        <PropertyGroup>
-            <StringifiedBravoProjectOutputs>@(BravoProjectOutputs)</StringifiedBravoProjectOutputs>
-            <StringifiedCharlieProjectOutputs>@(CharlieProjectOutputs)</StringifiedCharlieProjectOutputs>
-            <StringifiedDeltaProjectOutputs>@(DeltaProjectOutputs)</StringifiedDeltaProjectOutputs>
-        </PropertyGroup>
-
-        <!-- Explicitly build the metaproject generated for B -->
-        <MSBuild Projects='B.csproj.metaproj' Targets='Build'>
-            <Output
-                TaskParameter='TargetOutputs'
-                ItemName='BravoMetaProjectOutputs' />
-        </MSBuild>
-        <Message Importance='high' Text='BravoMetaProjectOutputs: @(BravoMetaProjectOutputs)' />
-        <Error Condition=` '@(BravoProjectOutputs)' != '@(BravoMetaProjectOutputs)' ` Text='Metaproj outputs must match outputs of normal project build.' />
-
-        <!-- Build the solution as a whole (which will build the metaproj and return overall outputs) -->
-        <MSBuild Projects='MSBuildIssue.sln'>
-            <Output
-                TaskParameter='TargetOutputs'
-                ItemName='SolutionProjectOutputs' />
-        </MSBuild>
-        <Message Importance='high' Text='SolutionProjectOutputs: @(SolutionProjectOutputs)' />
-        <Error Condition=` '@(SolutionProjectOutputs->Count())' != '3' ` Text='Overall sln outputs must include outputs of each referenced project (there should be 3).' />
-        <Error Condition=` '@(SolutionProjectOutputs->AnyHaveMetadataValue('Identity', '$(StringifiedBravoProjectOutputs)'))' != 'true'` Text='Overall sln outputs must include outputs of normal project build of project B.' />
-        <Error Condition=` '@(SolutionProjectOutputs->AnyHaveMetadataValue('Identity', '$(StringifiedCharlieProjectOutputs)'))' != 'true' ` Text='Overall sln outputs must include outputs of normal project build of project C.' />
-        <Error Condition=` '@(SolutionProjectOutputs->AnyHaveMetadataValue('Identity', '$(StringifiedDeltaProjectOutputs)'))' != 'true' ` Text='Overall sln outputs must include outputs of normal project build of project D.' />
-    </Target>
-</Project>";
+                    """;
+            const string automaticProjectFileContents =
+                """
+                <Project ToolsVersion='msbuilddefaulttoolsversion' DefaultTargets='compile' xmlns='msbuildnamespace'>
+                    <Target Name='compile'>
+                        <!-- Build projects to get a baseline for their output -->
+                        <MSBuild Projects='B.csproj' Targets='Build'>
+                            <Output
+                                TaskParameter='TargetOutputs'
+                                ItemName='BravoProjectOutputs' />
+                        </MSBuild>
+                        <Message Importance='high' Text='BravoProjectOutputs: @(BravoProjectOutputs)' />
+
+                        <MSBuild Projects='C.csproj' Targets='Build'>
+                            <Output
+                                TaskParameter='TargetOutputs'
+                                ItemName='CharlieProjectOutputs' />
+                        </MSBuild>
+                        <Message Importance='high' Text='CharlieProjectOutputs: @(CharlieProjectOutputs)' />
+
+                        <MSBuild Projects='D.csproj' Targets='Build'>
+                            <Output
+                                TaskParameter='TargetOutputs'
+                                ItemName='DeltaProjectOutputs' />
+                        </MSBuild>
+                        <Message Importance='high' Text='DeltaProjectOutputs: @(DeltaProjectOutputs)' />
+
+                        <PropertyGroup>
+                            <StringifiedBravoProjectOutputs>@(BravoProjectOutputs)</StringifiedBravoProjectOutputs>
+                            <StringifiedCharlieProjectOutputs>@(CharlieProjectOutputs)</StringifiedCharlieProjectOutputs>
+                            <StringifiedDeltaProjectOutputs>@(DeltaProjectOutputs)</StringifiedDeltaProjectOutputs>
+                        </PropertyGroup>
+
+                        <!-- Explicitly build the metaproject generated for B -->
+                        <MSBuild Projects='B.csproj.metaproj' Targets='Build'>
+                            <Output
+                                TaskParameter='TargetOutputs'
+                                ItemName='BravoMetaProjectOutputs' />
+                        </MSBuild>
+                        <Message Importance='high' Text='BravoMetaProjectOutputs: @(BravoMetaProjectOutputs)' />
+                        <Error Condition=` '@(BravoProjectOutputs)' != '@(BravoMetaProjectOutputs)' ` Text='Metaproj outputs must match outputs of normal project build.' />
+
+                        <!-- Build the solution as a whole (which will build the metaproj and return overall outputs) -->
+                        <MSBuild Projects='MSBuildIssue.sln'>
+                            <Output
+                                TaskParameter='TargetOutputs'
+                                ItemName='SolutionProjectOutputs' />
+                        </MSBuild>
+                        <Message Importance='high' Text='SolutionProjectOutputs: @(SolutionProjectOutputs)' />
+                        <Error Condition=` '@(SolutionProjectOutputs->Count())' != '3' ` Text='Overall sln outputs must include outputs of each referenced project (there should be 3).' />
+                        <Error Condition=` '@(SolutionProjectOutputs->AnyHaveMetadataValue('Identity', '$(StringifiedBravoProjectOutputs)'))' != 'true'` Text='Overall sln outputs must include outputs of normal project build of project B.' />
+                        <Error Condition=` '@(SolutionProjectOutputs->AnyHaveMetadataValue('Identity', '$(StringifiedCharlieProjectOutputs)'))' != 'true' ` Text='Overall sln outputs must include outputs of normal project build of project C.' />
+                        <Error Condition=` '@(SolutionProjectOutputs->AnyHaveMetadataValue('Identity', '$(StringifiedDeltaProjectOutputs)'))' != 'true' ` Text='Overall sln outputs must include outputs of normal project build of project D.' />
+                    </Target>
+                </Project>
+                """;
             #endregion
 
             var logger = new MockLogger(output);
@@ -1039,11 +1065,13 @@ public void SolutionConfigurationWithDependenciesRelaysItsOutputs()
         /// <summary>
         /// Test the SolutionProjectGenerator.AddPropertyGroupForSolutionConfiguration method
         /// </summary>
-        [Fact]
-        public void TestAddPropertyGroupForSolutionConfiguration()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void TestAddPropertyGroupForSolutionConfiguration(bool useNewParser)
         {
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 # Visual Studio 2005
                 Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'ClassLibrary1\ClassLibrary1.csproj', '{6185CC21-BE89-448A-B3C0-D1C27112E595}'
@@ -1063,9 +1091,9 @@ public void TestAddPropertyGroupForSolutionConfiguration()
                         {A6F99D27-47B9-4EA4-BFC9-25157CBDC281}.Debug|Mixed Platforms.Build.0 = VCConfig1|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectRootElement projectXml = ProjectRootElement.Create();
 
@@ -1112,11 +1140,13 @@ public void TestAddPropertyGroupForSolutionConfiguration()
         /// <summary>
         /// Make sure that BuildProjectInSolution is set to true of the Build.0 entry is in the solution configuration.
         /// </summary>
-        [Fact]
-        public void TestAddPropertyGroupForSolutionConfigurationBuildProjectInSolutionSet()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void TestAddPropertyGroupForSolutionConfigurationBuildProjectInSolutionSet(bool useNewParser)
         {
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 # Visual Studio 2005
                 Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'ClassLibrary1\ClassLibrary1.csproj', '{6185CC21-BE89-448A-B3C0-D1C27112E595}'
@@ -1131,9 +1161,9 @@ public void TestAddPropertyGroupForSolutionConfigurationBuildProjectInSolutionSe
                         {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Mixed Platforms.Build.0 = CSConfig1|Any CPU
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectRootElement projectXml = ProjectRootElement.Create();
 
@@ -1156,11 +1186,13 @@ public void TestAddPropertyGroupForSolutionConfigurationBuildProjectInSolutionSe
         /// <summary>
         /// Make sure that BuildProjectInSolution is set to false of the Build.0 entry is in the solution configuration.
         /// </summary>
-        [Fact]
-        public void TestAddPropertyGroupForSolutionConfigurationBuildProjectInSolutionNotSet()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void TestAddPropertyGroupForSolutionConfigurationBuildProjectInSolutionNotSet(bool useNewParser)
         {
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 # Visual Studio 2005
                 Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'ClassLibrary1\ClassLibrary1.csproj', '{6185CC21-BE89-448A-B3C0-D1C27112E595}'
@@ -1174,9 +1206,9 @@ public void TestAddPropertyGroupForSolutionConfigurationBuildProjectInSolutionNo
                         {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Mixed Platforms.ActiveCfg = CSConfig1|Any CPU
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectRootElement projectXml = ProjectRootElement.Create();
 
@@ -1200,10 +1232,12 @@ public void TestAddPropertyGroupForSolutionConfigurationBuildProjectInSolutionNo
         /// In this bug, SkipNonexistentProjects was always set to 'Build'. It should be 'Build' for metaprojects and 'True' for everything else.
         /// The repro below has one of each case. WebProjects can't build so they are set as SkipNonexistentProjects='Build'
         /// </summary>
-        [Fact]
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
         [Trait("Category", "netcore-osx-failing")]
         [Trait("Category", "netcore-linux-failing")]
-        public void Regress751742_SkipNonexistentProjects()
+        public void Regress751742_SkipNonexistentProjects(bool useNewParser)
         {
             if (FrameworkLocationHelper.PathToDotNetFrameworkV20 == null)
             {
@@ -1212,7 +1246,7 @@ public void Regress751742_SkipNonexistentProjects()
             }
 
             var solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 # Visual Studio 2005
                 Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'ClassLibrary1\ClassLibrary1.csproj', '{6185CC21-BE89-448A-B3C0-D1C27112E595}'
@@ -1232,10 +1266,10 @@ public void Regress751742_SkipNonexistentProjects()
                         {A6F99D27-47B9-4EA4-BFC9-25157CBDC281}.Debug|Mixed Platforms.Build.0 = VCConfig1|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
             // We're not passing in a /tv:xx switch, so the solution project will have tools version 2.0
-            var solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             var instance = SolutionProjectGenerator.Generate(solution, null, ObjectModelHelpers.MSBuildDefaultToolsVersion, _buildEventContext, CreateMockLoggingService())[0];
 
@@ -1274,11 +1308,13 @@ public void Regress751742_SkipNonexistentProjects()
         /// if set when building a solution, will be specified as the ToolsVersion on the MSBuild task when
         /// building the projects contained within the solution.
         /// </summary>
-        [Fact]
-        public void ToolsVersionOverrideShouldBeSpecifiedOnMSBuildTaskInvocations()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void ToolsVersionOverrideShouldBeSpecifiedOnMSBuildTaskInvocations(bool useNewParser)
         {
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 # Visual Studio 2005
                 Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'ClassLibrary1\ClassLibrary1.csproj', '{6185CC21-BE89-448A-B3C0-D1C27112E595}'
@@ -1298,10 +1334,10 @@ public void ToolsVersionOverrideShouldBeSpecifiedOnMSBuildTaskInvocations()
                         {A6F99D27-47B9-4EA4-BFC9-25157CBDC281}.Debug|Mixed Platforms.Build.0 = VCConfig1|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
             // We're not passing in a /tv:xx switch, so the solution project will have tools version 2.0
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, null, ObjectModelHelpers.MSBuildDefaultToolsVersion, _buildEventContext, CreateMockLoggingService());
 
@@ -1340,42 +1376,44 @@ public void ToolsVersionOverrideShouldBeSpecifiedOnMSBuildTaskInvocations()
         /// <summary>
         /// Make sure that whatever the solution ToolsVersion is, it gets mapped to all its metaprojs, too.
         /// </summary>
-        [Fact]
-        public void SolutionWithDependenciesHasCorrectToolsVersionInMetaprojs()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void SolutionWithDependenciesHasCorrectToolsVersionInMetaprojs(bool useNewParser)
         {
             string solutionFileContents =
-                @"
-Microsoft Visual Studio Solution File, Format Version 12.00
-Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ConsoleApplication2', 'ConsoleApplication2\ConsoleApplication2.csproj', '{5B97A3C7-3DEE-47A4-870F-5CB6384FE6A4}'
-    ProjectSection(ProjectDependencies) = postProject
-        {E0D295A1-CAFA-4E68-9929-468657DAAC6C} = {E0D295A1-CAFA-4E68-9929-468657DAAC6C}
-    EndProjectSection
-EndProject
-Project('{F184B08F-C81C-45F6-A57F-5ABD9991F28F}') = 'ConsoleApplication1', 'ConsoleApplication1\ConsoleApplication1.vbproj', '{E0D295A1-CAFA-4E68-9929-468657DAAC6C}'
-EndProject
-Global
-    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-        Debug|Any CPU = Debug|Any CPU
-        Release|Any CPU = Release|Any CPU
-    EndGlobalSection
-    GlobalSection(ProjectConfigurationPlatforms) = postSolution
-        {5B97A3C7-3DEE-47A4-870F-5CB6384FE6A4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-        {5B97A3C7-3DEE-47A4-870F-5CB6384FE6A4}.Debug|Any CPU.Build.0 = Debug|Any CPU
-        {5B97A3C7-3DEE-47A4-870F-5CB6384FE6A4}.Release|Any CPU.ActiveCfg = Release|Any CPU
-        {5B97A3C7-3DEE-47A4-870F-5CB6384FE6A4}.Release|Any CPU.Build.0 = Release|Any CPU
-        {E0D295A1-CAFA-4E68-9929-468657DAAC6C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-        {E0D295A1-CAFA-4E68-9929-468657DAAC6C}.Debug|Any CPU.Build.0 = Debug|Any CPU
-        {E0D295A1-CAFA-4E68-9929-468657DAAC6C}.Release|Any CPU.ActiveCfg = Release|Any CPU
-        {E0D295A1-CAFA-4E68-9929-468657DAAC6C}.Release|Any CPU.Build.0 = Release|Any CPU
-    EndGlobalSection
-    GlobalSection(SolutionProperties) = preSolution
-        HideSolutionNode = FALSE
-    EndGlobalSection
-EndGlobal
-                ";
+                """
+                Microsoft Visual Studio Solution File, Format Version 12.00
+                Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ConsoleApplication2', 'ConsoleApplication2\ConsoleApplication2.csproj', '{5B97A3C7-3DEE-47A4-870F-5CB6384FE6A4}'
+                    ProjectSection(ProjectDependencies) = postProject
+                        {E0D295A1-CAFA-4E68-9929-468657DAAC6C} = {E0D295A1-CAFA-4E68-9929-468657DAAC6C}
+                    EndProjectSection
+                EndProject
+                Project('{F184B08F-C81C-45F6-A57F-5ABD9991F28F}') = 'ConsoleApplication1', 'ConsoleApplication1\ConsoleApplication1.vbproj', '{E0D295A1-CAFA-4E68-9929-468657DAAC6C}'
+                EndProject
+                Global
+                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                        Debug|Any CPU = Debug|Any CPU
+                        Release|Any CPU = Release|Any CPU
+                    EndGlobalSection
+                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                        {5B97A3C7-3DEE-47A4-870F-5CB6384FE6A4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {5B97A3C7-3DEE-47A4-870F-5CB6384FE6A4}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                        {5B97A3C7-3DEE-47A4-870F-5CB6384FE6A4}.Release|Any CPU.ActiveCfg = Release|Any CPU
+                        {5B97A3C7-3DEE-47A4-870F-5CB6384FE6A4}.Release|Any CPU.Build.0 = Release|Any CPU
+                        {E0D295A1-CAFA-4E68-9929-468657DAAC6C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {E0D295A1-CAFA-4E68-9929-468657DAAC6C}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                        {E0D295A1-CAFA-4E68-9929-468657DAAC6C}.Release|Any CPU.ActiveCfg = Release|Any CPU
+                        {E0D295A1-CAFA-4E68-9929-468657DAAC6C}.Release|Any CPU.Build.0 = Release|Any CPU
+                    EndGlobalSection
+                    GlobalSection(SolutionProperties) = preSolution
+                        HideSolutionNode = FALSE
+                    EndGlobalSection
+                EndGlobal
+                """;
 
             // We're not passing in a /tv:xx switch, so the solution project will have tools version 2.0
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             string[] solutionToolsVersions = { "4.0", ObjectModelHelpers.MSBuildDefaultToolsVersion };
 
@@ -1409,11 +1447,13 @@ public void SolutionWithDependenciesHasCorrectToolsVersionInMetaprojs()
         /// <summary>
         /// Test the SolutionProjectGenerator.Generate method has its toolset redirected correctly.
         /// </summary>
-        [Fact]
-        public void ToolsVersionOverrideCausesToolsetRedirect()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void ToolsVersionOverrideCausesToolsetRedirect(bool useNewParser)
         {
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 # Visual Studio 2005
                 Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'ClassLibrary1', 'ClassLibrary1\ClassLibrary1.csproj', '{6185CC21-BE89-448A-B3C0-D1C27112E595}'
@@ -1433,8 +1473,8 @@ public void ToolsVersionOverrideCausesToolsetRedirect()
                         {A6F99D27-47B9-4EA4-BFC9-25157CBDC281}.Debug|Mixed Platforms.Build.0 = VCConfig1|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+                """;
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
             bool caughtException = false;
 
             try
@@ -1454,11 +1494,13 @@ public void ToolsVersionOverrideCausesToolsetRedirect()
         /// <summary>
         /// Test the SolutionProjectGenerator.AddPropertyGroupForSolutionConfiguration method
         /// </summary>
-        [Fact]
-        public void TestDisambiguateProjectTargetName()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void TestDisambiguateProjectTargetName(bool useNewParser)
         {
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 # Visual Studio 2005
                 Project('{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}') = 'Build', 'Build\Build.csproj', '{21397922-C38F-4A0E-B950-77B3FBD51881}'
@@ -1478,9 +1520,9 @@ public void TestDisambiguateProjectTargetName()
                                 HideSolutionNode = FALSE
                         EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, null, null, BuildEventContext.Invalid, CreateMockLoggingService());
 
@@ -1534,11 +1576,13 @@ public void TestDisambiguateProjectTargetName()
         /// <summary>
         /// Tests the algorithm for choosing default configuration/platform values for solutions
         /// </summary>
+        /// <remarks>This test would only work for the old parser. In the new parser SolutionConfigurations are not available,
+        /// and constructed from projects configurations.</remarks>
         [Fact]
         public void TestConfigurationPlatformDefaults1()
         {
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 Global
                     GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -1550,9 +1594,9 @@ public void TestConfigurationPlatformDefaults1()
                         Release|Win32 = Release|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = SolutionFile_OldParser_Tests.ParseSolutionHelper(solutionFileContents);
 
             // These used to exist on the engine, but now need to be passed in explicitly
             IDictionary<string, string> globalProperties = new Dictionary<string, string>();
@@ -1572,11 +1616,13 @@ public void TestConfigurationPlatformDefaults1()
         /// <summary>
         /// Tests the algorithm for choosing default configuration/platform values for solutions
         /// </summary>
+        /// <remarks>This test would only work for the old parser. In the new parser SolutionConfigurations are not available,
+        /// and constructed from projects configurations.</remarks>
         [Fact]
         public void TestConfigurationPlatformDefaults2()
         {
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 Global
                     GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -1586,9 +1632,9 @@ public void TestConfigurationPlatformDefaults2()
                         Other|Win32 = Other|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = SolutionFile_OldParser_Tests.ParseSolutionHelper(solutionFileContents);
 
             ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, null, null, BuildEventContext.Invalid, CreateMockLoggingService());
 
@@ -1602,10 +1648,12 @@ public void TestConfigurationPlatformDefaults2()
         /// <summary>
         /// Tests the algorithm for choosing default Venus configuration values for solutions
         /// </summary>
-        [Fact]
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
         [Trait("Category", "netcore-osx-failing")]
         [Trait("Category", "netcore-linux-failing")]
-        public void TestVenusConfigurationDefaults()
+        public void TestVenusConfigurationDefaults(bool useNewParser)
         {
             if (FrameworkLocationHelper.PathToDotNetFrameworkV20 == null)
             {
@@ -1615,13 +1663,13 @@ public void TestVenusConfigurationDefaults()
 
             Dictionary<string, string> globalProperties = new Dictionary<string, string>();
             globalProperties["Configuration"] = "Debug";
-            ProjectInstance msbuildProject = CreateVenusSolutionProject(globalProperties);
+            ProjectInstance msbuildProject = CreateVenusSolutionProject(globalProperties, useNewParser);
 
             // ASP.NET configuration should match the selected solution configuration
             Assert.Equal("Debug", msbuildProject.GetPropertyValue("AspNetConfiguration"));
 
             globalProperties["Configuration"] = "Release";
-            msbuildProject = CreateVenusSolutionProject(globalProperties);
+            msbuildProject = CreateVenusSolutionProject(globalProperties, useNewParser);
             Assert.Equal("Release", msbuildProject.GetPropertyValue("AspNetConfiguration"));
 
             // Check that the two standard Asp.net configurations are represented on the targets
@@ -1632,10 +1680,12 @@ public void TestVenusConfigurationDefaults()
         /// <summary>
         /// Tests that the correct value for TargetFrameworkVersion gets set when creating Venus solutions
         /// </summary>
-        [Fact]
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
         [Trait("Category", "netcore-osx-failing")]
         [Trait("Category", "netcore-linux-failing")]
-        public void VenusSolutionDefaultTargetFrameworkVersion()
+        public void VenusSolutionDefaultTargetFrameworkVersion(bool useNewParser)
         {
             if (FrameworkLocationHelper.PathToDotNetFrameworkV20 == null)
             {
@@ -1644,7 +1694,7 @@ public void VenusSolutionDefaultTargetFrameworkVersion()
             }
 
             // v4.0 by default
-            ProjectInstance msbuildProject = CreateVenusSolutionProject();
+            ProjectInstance msbuildProject = CreateVenusSolutionProject(useNewParser);
             Assert.Equal("v4.0", msbuildProject.GetPropertyValue("TargetFrameworkVersion"));
 
             if (FrameworkLocationHelper.PathToDotNetFrameworkV35 == null)
@@ -1654,34 +1704,36 @@ public void VenusSolutionDefaultTargetFrameworkVersion()
             }
 
             // v3.5 if MSBuildToolsVersion is 3.5
-            msbuildProject = CreateVenusSolutionProject("3.5");
+            msbuildProject = CreateVenusSolutionProject("3.5", useNewParser);
             Assert.Equal("v3.5", msbuildProject.GetPropertyValue("TargetFrameworkVersion"));
 
             // v2.0 if MSBuildToolsVersion is 2.0
-            msbuildProject = CreateVenusSolutionProject("2.0");
+            msbuildProject = CreateVenusSolutionProject("2.0", useNewParser);
             Assert.Equal("v2.0", msbuildProject.GetPropertyValue("TargetFrameworkVersion"));
 
             // may be user defined
             IDictionary<string, string> globalProperties = new Dictionary<string, string>();
             globalProperties.Add("TargetFrameworkVersion", "userdefined");
-            msbuildProject = CreateVenusSolutionProject(globalProperties);
+            msbuildProject = CreateVenusSolutionProject(globalProperties, useNewParser);
             Assert.Equal("userdefined", msbuildProject.GetPropertyValue("TargetFrameworkVersion"));
         }
 
         /// <summary>
         /// Tests the algorithm for choosing target framework paths for ResolveAssemblyReferences for Venus
         /// </summary>
-        [Fact]
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
         [Trait("Category", "netcore-osx-failing")]
         [Trait("Category", "netcore-linux-failing")]
-        public void TestTargetFrameworkPaths0()
+        public void TestTargetFrameworkPaths0(bool useNewParser)
         {
             if (FrameworkLocationHelper.PathToDotNetFrameworkSdkV20 != null)
             {
                 IDictionary<string, string> globalProperties = new Dictionary<string, string>();
                 globalProperties.Add("TargetFrameworkVersion", "v2.0");
 
-                ProjectInstance msbuildProject = CreateVenusSolutionProject("2.0");
+                ProjectInstance msbuildProject = CreateVenusSolutionProject("2.0", useNewParser);
 
                 // ToolsVersion is 2.0, TargetFrameworkVersion is v2.0 --> one item pointing to v2.0
                 Assert.Equal("2.0", msbuildProject.ToolsVersion);
@@ -1696,10 +1748,12 @@ public void TestTargetFrameworkPaths0()
         /// <summary>
         /// Tests the algorithm for choosing target framework paths for ResolveAssemblyReferences for Venus
         /// </summary>
-        [Fact]
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
         [Trait("Category", "netcore-osx-failing")]
         [Trait("Category", "netcore-linux-failing")]
-        public void TestTargetFrameworkPaths1()
+        public void TestTargetFrameworkPaths1(bool useNewParser)
         {
             if (FrameworkLocationHelper.PathToDotNetFrameworkV20 == null)
             {
@@ -1707,7 +1761,7 @@ public void TestTargetFrameworkPaths1()
                 return;
             }
 
-            ProjectInstance msbuildProject = CreateVenusSolutionProject();
+            ProjectInstance msbuildProject = CreateVenusSolutionProject(useNewParser);
 
             // ToolsVersion is 4.0, TargetFrameworkVersion is v2.0 --> one item pointing to v2.0
             msbuildProject.SetProperty("TargetFrameworkVersion", "v2.0");
@@ -1722,10 +1776,12 @@ public void TestTargetFrameworkPaths1()
         /// <summary>
         /// Tests the algorithm for choosing target framework paths for ResolveAssemblyReferences for Venus
         /// </summary>
-        [Fact]
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
         [Trait("Category", "netcore-osx-failing")]
         [Trait("Category", "netcore-linux-failing")]
-        public void TestTargetFrameworkPaths2()
+        public void TestTargetFrameworkPaths2(bool useNewParser)
         {
             if (FrameworkLocationHelper.PathToDotNetFrameworkV20 == null)
             {
@@ -1733,7 +1789,7 @@ public void TestTargetFrameworkPaths2()
                 return;
             }
 
-            ProjectInstance msbuildProject = CreateVenusSolutionProject();
+            ProjectInstance msbuildProject = CreateVenusSolutionProject(useNewParser);
 
             // ToolsVersion is 4.0, TargetFrameworkVersion is v4.0 --> items for v2.0 and v4.0
             msbuildProject.SetProperty("TargetFrameworkVersion", "v4.0");
@@ -1771,11 +1827,13 @@ public void TestTargetFrameworkPaths2()
         /// <summary>
         /// Test the PredictActiveSolutionConfigurationName method
         /// </summary>
+        /// <remarks>This test would only work for the old parser.
+        /// In the new parser SolutionConfigurations are not available, and constructed from projects configurations.</remarks>
         [Fact]
         public void TestPredictSolutionConfigurationName()
         {
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 Global
                     GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -1785,9 +1843,9 @@ public void TestPredictSolutionConfigurationName()
                         Debug|Win32 = Debug|Win32
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = SolutionFile_OldParser_Tests.ParseSolutionHelper(solutionFileContents);
 
             IDictionary<string, string> globalProperties = new Dictionary<string, string>();
 
@@ -1806,11 +1864,13 @@ public void TestPredictSolutionConfigurationName()
         /// <summary>
         /// Verifies that the SolutionProjectGenerator will correctly escape project file paths
         /// </summary>
-        [Fact]
-        public void SolutionGeneratorEscapingProjectFilePaths()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void SolutionGeneratorEscapingProjectFilePaths(bool useNewParser)
         {
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 # Visual Studio 2005
                 Project('{F184B08F-C81C-45F6-A57F-5ABD9991F28F}') = 'ConsoleApplication1', '%abtest\ConsoleApplication1.vbproj', '{AB3413A6-D689-486D-B7F0-A095371B3F13}'
@@ -1830,9 +1890,9 @@ public void SolutionGeneratorEscapingProjectFilePaths()
                         HideSolutionNode = FALSE
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             // Creating a ProjectRootElement shouldn't affect the ProjectCollection at all
             Assert.Empty(ProjectCollection.GlobalProjectCollection.LoadedProjects);
@@ -1849,8 +1909,10 @@ public void SolutionGeneratorEscapingProjectFilePaths()
         /// <summary>
         /// Verifies that the SolutionProjectGenerator will emit a solution file.
         /// </summary>
-        [Fact]
-        public void SolutionGeneratorCanEmitSolutions()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void SolutionGeneratorCanEmitSolutions(bool useNewParser)
         {
             string oldValueForMSBuildEmitSolution = Environment.GetEnvironmentVariable("MSBuildEmitSolution");
 
@@ -1858,7 +1920,7 @@ public void SolutionGeneratorCanEmitSolutions()
             ProjectCollection.GlobalProjectCollection.UnloadAllProjects();
 
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 # Visual Studio 2005
                 Project('{F184B08F-C81C-45F6-A57F-5ABD9991F28F}') = 'ConsoleApplication1', 'ConsoleApplication1\ConsoleApplication1.vbproj', '{AB3413A6-D689-486D-B7F0-A095371B3F13}'
@@ -1878,7 +1940,7 @@ public void SolutionGeneratorCanEmitSolutions()
                         HideSolutionNode = FALSE
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
             SolutionFile solution = null;
             using ProjectCollection collection = new ProjectCollection();
@@ -1887,7 +1949,7 @@ public void SolutionGeneratorCanEmitSolutions()
             {
                 Environment.SetEnvironmentVariable("MSBuildEmitSolution", "1");
 
-                solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+                solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
                 // Creating a ProjectRootElement shouldn't affect the ProjectCollection at all
                 Assert.Empty(ProjectCollection.GlobalProjectCollection.LoadedProjects);
@@ -1919,16 +1981,18 @@ public void SolutionGeneratorCanEmitSolutions()
         /// Make sure that we output a warning and don't build anything when we're given an invalid
         /// solution configuration and SkipInvalidConfigurations is set to true.
         /// </summary>
-        [Fact]
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
         [Trait("Category", "netcore-osx-failing")]
         [Trait("Category", "netcore-linux-failing")]
-        public void TestSkipInvalidConfigurationsCase()
+        public void TestSkipInvalidConfigurationsCase(bool useNewParser)
         {
             string tmpFileName = FileUtilities.GetTemporaryFileName();
             string projectFilePath = tmpFileName + ".sln";
 
-            string solutionContents =
-                @"
+            string solutionFileContents =
+                """
                 Microsoft Visual Studio Solution File, Format Version 11.00
                 # Visual Studio 2005
                 Project('{E24C65DC-7377-472B-9ABA-BC803B73C61A}') = 'C:\solutions\WebSite2\', '..\..\solutions\WebSite2\', '{F90528C4-6989-4D33-AFE8-F53173597CC2}'
@@ -1959,7 +2023,8 @@ public void TestSkipInvalidConfigurationsCase()
                         {F90528C4-6989-4D33-AFE8-F53173597CC2}.Debug|Any CPU.ActiveCfg = Debug|.NET
                         {F90528C4-6989-4D33-AFE8-F53173597CC2}.Debug|Any CPU.Build.0 = Debug|.NET
                     EndGlobalSection
-                EndGlobal";
+                EndGlobal
+                """;
 
             try
             {
@@ -1969,7 +2034,7 @@ public void TestSkipInvalidConfigurationsCase()
                 globalProperties["Configuration"] = "Nonexistent";
                 globalProperties["SkipInvalidConfigurations"] = "true";
 
-                SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionContents.Replace('\'', '"'));
+                SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
                 ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, globalProperties, null, BuildEventContext.Invalid, CreateMockLoggingService());
                 ProjectInstance msbuildProject = instances[0];
 
@@ -2173,50 +2238,52 @@ public void BadFrameworkMonkierExpectBuildToFail2()
         /// Bug indicated that when a target framework version greater than 4.0 was used then the solution project generator would crash.
         /// this test is to make sure the fix is not regressed.
         /// </summary>
-        [Fact]
-        public void TestTargetFrameworkVersionGreaterThan4()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void TestTargetFrameworkVersionGreaterThan4(bool useNewParser)
         {
             string tmpFileName = FileUtilities.GetTemporaryFileName();
             string projectFilePath = tmpFileName + ".sln";
 
             string solutionFileContents =
-               @"
-Microsoft Visual Studio Solution File, Format Version 11.00
-# Visual Studio 2010
-Project('{E24C65DC-7377-472B-9ABA-BC803B73C61A}') = 'WebSite1', '..\WebSite1\', '{6B8F98F2-C976-4029-9321-5CCD73A174DA}'
-    ProjectSection(WebsiteProperties) = preProject
-        TargetFrameworkMoniker = '.NETFramework,Version=v4.34'
-        Debug.AspNetCompiler.VirtualPath = '/WebSite1'
-        Debug.AspNetCompiler.PhysicalPath = '..\WebSite1\'
-        Debug.AspNetCompiler.TargetPath = 'PrecompiledWeb\WebSite1\'
-        Debug.AspNetCompiler.Updateable = 'true'
-        Debug.AspNetCompiler.ForceOverwrite = 'true'
-        Debug.AspNetCompiler.FixedNames = 'false'
-        Debug.AspNetCompiler.Debug = 'True'
-        Release.AspNetCompiler.VirtualPath = '/WebSite1'
-        Release.AspNetCompiler.PhysicalPath = '..\WebSite1\'
-        Release.AspNetCompiler.TargetPath = 'PrecompiledWeb\WebSite1\'
-        Release.AspNetCompiler.Updateable = 'true'
-        Release.AspNetCompiler.ForceOverwrite = 'true'
-        Release.AspNetCompiler.FixedNames = 'false'
-        Release.AspNetCompiler.Debug = 'False'
-        VWDPort = '45602'
-        DefaultWebSiteLanguage = 'Visual Basic'
-    EndProjectSection
-EndProject
-Global
-    GlobalSection(SolutionConfigurationPlatforms) = preSolution
-        Debug|Any CPU = Debug|Any CPU
-    EndGlobalSection
-    GlobalSection(ProjectConfigurationPlatforms) = postSolution
-        {6B8F98F2-C976-4029-9321-5CCD73A174DA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-        {6B8F98F2-C976-4029-9321-5CCD73A174DA}.Debug|Any CPU.Build.0 = Debug|Any CPU
-    EndGlobalSection
-    GlobalSection(SolutionProperties) = preSolution
-        HideSolutionNode = FALSE
-    EndGlobalSection
-EndGlobal
-                ";
+               """
+                Microsoft Visual Studio Solution File, Format Version 11.00
+                # Visual Studio 2010
+                Project('{E24C65DC-7377-472B-9ABA-BC803B73C61A}') = 'WebSite1', '..\WebSite1\', '{6B8F98F2-C976-4029-9321-5CCD73A174DA}'
+                    ProjectSection(WebsiteProperties) = preProject
+                        TargetFrameworkMoniker = '.NETFramework,Version=v4.34'
+                        Debug.AspNetCompiler.VirtualPath = '/WebSite1'
+                        Debug.AspNetCompiler.PhysicalPath = '..\WebSite1\'
+                        Debug.AspNetCompiler.TargetPath = 'PrecompiledWeb\WebSite1\'
+                        Debug.AspNetCompiler.Updateable = 'true'
+                        Debug.AspNetCompiler.ForceOverwrite = 'true'
+                        Debug.AspNetCompiler.FixedNames = 'false'
+                        Debug.AspNetCompiler.Debug = 'True'
+                        Release.AspNetCompiler.VirtualPath = '/WebSite1'
+                        Release.AspNetCompiler.PhysicalPath = '..\WebSite1\'
+                        Release.AspNetCompiler.TargetPath = 'PrecompiledWeb\WebSite1\'
+                        Release.AspNetCompiler.Updateable = 'true'
+                        Release.AspNetCompiler.ForceOverwrite = 'true'
+                        Release.AspNetCompiler.FixedNames = 'false'
+                        Release.AspNetCompiler.Debug = 'False'
+                        VWDPort = '45602'
+                        DefaultWebSiteLanguage = 'Visual Basic'
+                    EndProjectSection
+                EndProject
+                Global
+                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                        Debug|Any CPU = Debug|Any CPU
+                    EndGlobalSection
+                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                        {6B8F98F2-C976-4029-9321-5CCD73A174DA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {6B8F98F2-C976-4029-9321-5CCD73A174DA}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                    EndGlobalSection
+                    GlobalSection(SolutionProperties) = preSolution
+                        HideSolutionNode = FALSE
+                    EndGlobalSection
+                EndGlobal
+                """;
 
             try
             {
@@ -2226,7 +2293,9 @@ public void TestTargetFrameworkVersionGreaterThan4()
                 globalProperties["Configuration"] = "Release";
                 globalProperties["SkipInvalidConfigurations"] = "true";
 
-                SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents.Replace('\'', '"'));
+
+                SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
+
                 using ProjectCollection collection = new ProjectCollection();
                 collection.RegisterLogger(logger);
 
@@ -2256,14 +2325,16 @@ public void TestTargetFrameworkVersionGreaterThan4()
         /// <summary>
         /// Verifies that when target names are specified they end up in the metaproj.
         /// </summary>
-        [Fact]
-        public void CustomTargetNamesAreInInMetaproj()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void CustomTargetNamesAreInInMetaproj(bool useNewParser)
         {
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(
-            @"
-                Microsoft Visual Studio Solution File, Format Version 14.00
+            string solutionFileContents =
+                """
+                Microsoft Visual Studio Solution File, Format Version 12.00
                 # Visual Studio 2015
-                Project(""{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"") = ""ClassLibrary1"", ""ClassLibrary1.csproj"", ""{6185CC21-BE89-448A-B3C0-D1C27112E595}""
+                Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ClassLibrary1", "ClassLibrary1.csproj", "{6185CC21-BE89-448A-B3C0-D1C27112E595}"
                 EndProject
                 Global
                     GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -2275,7 +2346,9 @@ public void CustomTargetNamesAreInInMetaproj()
                         {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.ActiveCfg = CSConfig2|Any CPU
                     EndGlobalSection
                 EndGlobal
-            ");
+                """;
+
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, null, null, BuildEventContext.Invalid, CreateMockLoggingService(), new List<string> { "One" });
 
@@ -2304,14 +2377,16 @@ public void CustomTargetNamesAreInInMetaproj()
         /// <summary>
         /// Verifies that disambiguated target names are used when a project name matches a standard solution entry point.
         /// </summary>
-        [Fact]
-        public void DisambiguatedTargetNamesAreInInMetaproj()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void DisambiguatedTargetNamesAreInMetaproj(bool useNewParser)
         {
-            foreach(string projectName in ProjectInSolution.projectNamesToDisambiguate)
+            foreach (string projectName in ProjectInSolution.projectNamesToDisambiguate)
             {
-                SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(
-                $$"""
-                    Microsoft Visual Studio Solution File, Format Version 14.00
+                string solutionFileContents =
+                    $$"""
+                    Microsoft Visual Studio Solution File, Format Version 12.00
                     # Visual Studio 2015
                     Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "{{projectName}}", "{{projectName}}.csproj", "{6185CC21-BE89-448A-B3C0-D1C27112E595}"
                     EndProject
@@ -2326,7 +2401,9 @@ public void DisambiguatedTargetNamesAreInInMetaproj()
                             {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.Build.0 = Release|Any CPU
                         EndGlobalSection
                     EndGlobal
-                """);
+                    """;
+
+                SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
                 ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, null, null, BuildEventContext.Invalid, CreateMockLoggingService(), null);
 
@@ -2349,29 +2426,33 @@ public void DisambiguatedTargetNamesAreInInMetaproj()
         /// Verifies that illegal user target names (the ones already used internally) don't crash the SolutionProjectGenerator
         /// </summary>
         [Theory]
-        [InlineData(false)]
-        [InlineData(true)]
-        public void IllegalUserTargetNamesDoNotThrow(bool forceCaseDifference)
+        [InlineData(false, false)]
+        [InlineData(true, false)]
+        [InlineData(false, true)]
+        [InlineData(true, true)]
+        public void IllegalUserTargetNamesDoNotThrow(bool forceCaseDifference, bool useNewParser)
         {
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(
-            @"
-                Microsoft Visual Studio Solution File, Format Version 14.00
+            string solutionFileContents =
+                """
+                Microsoft Visual Studio Solution File, Format Version 12.00
                 # Visual Studio 2015
-                Project(""{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"") = ""ClassLibrary1"", ""ClassLibrary1.csproj"", ""{6185CC21-BE89-448A-B3C0-D1C27112E595}""
+                Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ClassLibrary1", "ClassLibrary1.csproj", "{6185CC21-BE89-448A-B3C0-D1C27112E595}"
                 EndProject
                 Global
-	                GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		                Debug|Any CPU = Debug|Any CPU
-		                Release|Any CPU = Release|Any CPU
-	                EndGlobalSection
-	                GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.Build.0 = Release|Any CPU
-	                EndGlobalSection
+                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                        Debug|Any CPU = Debug|Any CPU
+                        Release|Any CPU = Release|Any CPU
+                    EndGlobalSection
+                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.ActiveCfg = Release|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.Build.0 = Release|Any CPU
+                    EndGlobalSection
                 EndGlobal
-            ");
+                """;
+
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectInstance[] instances;
 
@@ -2426,31 +2507,34 @@ public void AfterTargetsComeFromImport()
         {
             string baseDirectory = Guid.NewGuid().ToString("N");
 
-            string solutionFilePath = ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, $"{Guid.NewGuid():N}.sln"), @"
-                Microsoft Visual Studio Solution File, Format Version 14.00
+            string solutionFilePath = ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, $"{Guid.NewGuid():N}.sln"),
+                """
+                Microsoft Visual Studio Solution File, Format Version 12.00
                 # Visual Studio 2015
-                Project(""{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"") = ""ClassLibrary1"", ""ClassLibrary1.csproj"", ""{6185CC21-BE89-448A-B3C0-D1C27112E595}""
+                Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ClassLibrary1", "ClassLibrary1.csproj", "{6185CC21-BE89-448A-B3C0-D1C27112E595}"
                 EndProject
                 Global
-	                GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		                Debug|Any CPU = Debug|Any CPU
-		                Release|Any CPU = Release|Any CPU
-	                EndGlobalSection
-	                GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.Build.0 = Release|Any CPU
-	                EndGlobalSection
+                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                        Debug|Any CPU = Debug|Any CPU
+                        Release|Any CPU = Release|Any CPU
+                    EndGlobalSection
+                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.ActiveCfg = Release|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.Build.0 = Release|Any CPU
+                    EndGlobalSection
                 EndGlobal
-            ");
+                """);
 
-            ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, $"after.{Path.GetFileName(solutionFilePath)}.targets"), @"
-                <Project ToolsVersion=""msbuilddefaulttoolsversion"" xmlns=""msbuildnamespace"">
-                    <Target Name=""MyTarget"">
+            ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, $"after.{Path.GetFileName(solutionFilePath)}.targets"),
+                """
+                <Project ToolsVersion="msbuilddefaulttoolsversion" xmlns="msbuildnamespace">
+                    <Target Name="MyTarget">
                         <MyTask />
                     </Target>
-                </Project>");
+                </Project>
+                """);
 
             try
             {
@@ -2482,31 +2566,34 @@ public void BeforeTargetsFromImportCanHookDynamicTarget()
         {
             string baseDirectory = Guid.NewGuid().ToString("N");
 
-            string solutionFilePath = ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, $"{Guid.NewGuid():N}.sln"), @"
-                Microsoft Visual Studio Solution File, Format Version 14.00
+            string solutionFilePath = ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, $"{Guid.NewGuid():N}.sln"),
+                """
+                Microsoft Visual Studio Solution File, Format Version 12.00
                 # Visual Studio 2015
-                Project(""{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"") = ""ClassLibrary1"", ""ClassLibrary1.csproj"", ""{6185CC21-BE89-448A-B3C0-D1C27112E595}""
+                Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ClassLibrary1", "ClassLibrary1.csproj", "{6185CC21-BE89-448A-B3C0-D1C27112E595}"
                 EndProject
                 Global
-	                GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		                Debug|Any CPU = Debug|Any CPU
-		                Release|Any CPU = Release|Any CPU
-	                EndGlobalSection
-	                GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.Build.0 = Release|Any CPU
-	                EndGlobalSection
+                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                        Debug|Any CPU = Debug|Any CPU
+                        Release|Any CPU = Release|Any CPU
+                    EndGlobalSection
+                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.ActiveCfg = Release|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.Build.0 = Release|Any CPU
+                    EndGlobalSection
                 EndGlobal
-            ");
+                """);
 
-            ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, $"after.{Path.GetFileName(solutionFilePath)}.targets"), @"
-                <Project ToolsVersion=""msbuilddefaulttoolsversion"" xmlns=""msbuildnamespace"">
-                    <Target Name=""MyTarget"" BeforeTargets=""DynamicTraversalTarget"">
-                        <Warning Text=""Message from MyTarget"" />
+            ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, $"after.{Path.GetFileName(solutionFilePath)}.targets"),
+                """
+                <Project ToolsVersion="msbuilddefaulttoolsversion" xmlns="msbuildnamespace">
+                    <Target Name="MyTarget" BeforeTargets="DynamicTraversalTarget">
+                        <Warning Text="Message from MyTarget" />
                     </Target>
-                </Project>");
+                </Project>
+                """);
 
             try
             {
@@ -2557,48 +2644,55 @@ public void DirectorySolutionPropsTest(string projectName, bool enable)
 
             string baseDirectory = Guid.NewGuid().ToString("N");
 
-            string solutionFilePath = ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, $"{Guid.NewGuid():N}.sln"), @"
-                Microsoft Visual Studio Solution File, Format Version 14.00
+            string solutionFilePath = ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, $"{Guid.NewGuid():N}.sln"),
+                """
+                Microsoft Visual Studio Solution File, Format Version 12.00
                 # Visual Studio 2015
-                Project(""{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}"") = ""ClassLibrary1"", ""ClassLibrary1.csproj"", ""{6185CC21-BE89-448A-B3C0-D1C27112E595}""
+                Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ClassLibrary1", "ClassLibrary1.csproj", "{6185CC21-BE89-448A-B3C0-D1C27112E595}"
                 EndProject
                 Global
-	                GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		                Debug|Any CPU = Debug|Any CPU
-		                Release|Any CPU = Release|Any CPU
-	                EndGlobalSection
-	                GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		                {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.Build.0 = Release|Any CPU
-	                EndGlobalSection
+                    GlobalSection(SolutionConfigurationPlatforms) = preSolution
+                        Debug|Any CPU = Debug|Any CPU
+                        Release|Any CPU = Release|Any CPU
+                    EndGlobalSection
+                    GlobalSection(ProjectConfigurationPlatforms) = postSolution
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Debug|Any CPU.Build.0 = Debug|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.ActiveCfg = Release|Any CPU
+                        {6185CC21-BE89-448A-B3C0-D1C27112E595}.Release|Any CPU.Build.0 = Release|Any CPU
+                    EndGlobalSection
                 EndGlobal
-            ");
+                """);
 
-            string projectPath = ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, projectName), $@"
-                <Project ToolsVersion=""msbuilddefaulttoolsversion"" xmlns=""msbuildnamespace"">
+            string projectPath = ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, projectName),
+                $$"""
+                <Project ToolsVersion="msbuilddefaulttoolsversion" xmlns="msbuildnamespace">
                     <PropertyGroup>
-                        <PropertyA>{expectedPropertyValue}</PropertyA>
+                        <PropertyA>{{expectedPropertyValue}}</PropertyA>
                     </PropertyGroup>
-                </Project>");
+                </Project>
+                """);
 
             if (projectPath.StartsWith("Custom", StringComparison.OrdinalIgnoreCase))
             {
                 // If a custom file name was given, create a Directory.Solution.props and Directory.Build.targets to ensure that they aren't imported
-                ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, "Directory.Solution.props"), $@"
-                <Project ToolsVersion=""msbuilddefaulttoolsversion"" xmlns=""msbuildnamespace"">
-                    <PropertyGroup>
-                        <PropertyA>This file should not be imported</PropertyA>
-                    </PropertyGroup>
-                </Project>");
-
-                ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, "Directory.Solution.targets"), $@"
-                <Project ToolsVersion=""msbuilddefaulttoolsversion"" xmlns=""msbuildnamespace"">
-                    <PropertyGroup>
-                        <PropertyA>This file should not be imported</PropertyA>
-                    </PropertyGroup>
-                </Project>");
+                ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, "Directory.Solution.props"),
+                    """
+                    <Project ToolsVersion="msbuilddefaulttoolsversion" xmlns="msbuildnamespace">
+                        <PropertyGroup>
+                            <PropertyA>This file should not be imported</PropertyA>
+                        </PropertyGroup>
+                    </Project>
+                    """);
+
+                ObjectModelHelpers.CreateFileInTempProjectDirectory(Path.Combine(baseDirectory, "Directory.Solution.targets"),
+                    """
+                    <Project ToolsVersion="msbuilddefaulttoolsversion" xmlns="msbuildnamespace">
+                        <PropertyGroup>
+                            <PropertyA>This file should not be imported</PropertyA>
+                        </PropertyGroup>
+                    </Project>
+                    """);
             }
 
             try
@@ -2640,20 +2734,23 @@ public void DirectorySolutionPropsTest(string projectName, bool enable)
         /// Regression test for https://github.com/dotnet/msbuild/issues/6236
         /// </summary>
         [Theory]
-        [InlineData("http://localhost:8080")]
-        [InlineData("a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-a-really-long-string-")]
-        public void AbsolutePathWorksForUnsupportedPaths(string relativePath)
+        [InlineData("http://localhost:8080", false)]
+        [InlineData("http://localhost:8080", true)]
+        [InlineData(_longLineString, false)]
+        [InlineData(_longLineString, true)]
+        public void AbsolutePathWorksForUnsupportedPaths(string relativePath, bool useNewParser)
         {
             string solutionFileContents =
-                $@"
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
-VisualStudioVersion = 16.0.31025.194
-MinimumVisualStudioVersion = 10.0.40219.1
-Project(""{{E24C65DC-7377-472B-9ABA-BC803B73C61A}}"") = ""WebSite1"", ""{relativePath}"", ""{{{{96E0707C-2E9C-4704-946F-FA583147737F}}}}""
-EndProject";
+                $$"""
+                Microsoft Visual Studio Solution File, Format Version 12.00
+                # Visual Studio Version 16
+                VisualStudioVersion = 16.0.31025.194
+                MinimumVisualStudioVersion = 10.0.40219.1
+                Project("{E24C65DC-7377-472B-9ABA-BC803B73C61A}") = "WebSite1", "{{relativePath}}", "{96E0707C-2E9C-4704-946F-FA583147737F}"
+                EndProject
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectInSolution projectInSolution = solution.ProjectsInOrder.ShouldHaveSingleItem();
 
@@ -2665,25 +2762,25 @@ public void AbsolutePathWorksForUnsupportedPaths(string relativePath)
         /// <summary>
         /// Create a Project derived from a Venus solution
         /// </summary>
-        private ProjectInstance CreateVenusSolutionProject()
+        private ProjectInstance CreateVenusSolutionProject(bool useNewParser)
         {
-            return CreateVenusSolutionProject(null, null);
+            return CreateVenusSolutionProject(null, null, useNewParser);
         }
 
         /// <summary>
         /// Create a Project derived from a Venus solution
         /// </summary>
-        private ProjectInstance CreateVenusSolutionProject(IDictionary<string, string> globalProperties)
+        private ProjectInstance CreateVenusSolutionProject(IDictionary<string, string> globalProperties, bool useNewParser)
         {
-            return CreateVenusSolutionProject(globalProperties, null);
+            return CreateVenusSolutionProject(globalProperties, null, useNewParser);
         }
 
         /// <summary>
         /// Create a Project derived from a Venus solution
         /// </summary>
-        private ProjectInstance CreateVenusSolutionProject(string toolsVersion)
+        private ProjectInstance CreateVenusSolutionProject(string toolsVersion, bool useNewParser)
         {
-            return CreateVenusSolutionProject(null, toolsVersion);
+            return CreateVenusSolutionProject(null, toolsVersion, useNewParser);
         }
 
         /// <summary>
@@ -2692,10 +2789,10 @@ private ProjectInstance CreateVenusSolutionProject(string toolsVersion)
         /// </summary>
         /// <param name="globalProperties">The dictionary of global properties.  May be null.</param>
         /// <param name="toolsVersion">The ToolsVersion override value.  May be null.</param>
-        private ProjectInstance CreateVenusSolutionProject(IDictionary<string, string> globalProperties, string toolsVersion)
+        private ProjectInstance CreateVenusSolutionProject(IDictionary<string, string> globalProperties, string toolsVersion, bool useNewParser)
         {
             string solutionFileContents =
-                @"
+                """
                 Microsoft Visual Studio Solution File, Format Version 9.00
                 # Visual Studio 2005
                 Project('{E24C65DC-7377-472B-9ABA-BC803B73C61A}') = 'C:\solutions\WebSite2\', '..\..\solutions\WebSite2\', '{F90528C4-6989-4D33-AFE8-F53173597CC2}'
@@ -2727,9 +2824,9 @@ private ProjectInstance CreateVenusSolutionProject(IDictionary<string, string> g
                         {F90528C4-6989-4D33-AFE8-F53173597CC2}.Debug|Any CPU.Build.0 = Debug|.NET
                     EndGlobalSection
                 EndGlobal
-                ";
+                """;
 
-            SolutionFile solution = SolutionFile_Tests.ParseSolutionHelper(solutionFileContents);
+            SolutionFile solution = ParseSolutionHelper(solutionFileContents, useNewParser);
 
             ProjectInstance[] instances = SolutionProjectGenerator.Generate(solution, globalProperties, toolsVersion, BuildEventContext.Invalid, CreateMockLoggingService());
 
@@ -2776,6 +2873,12 @@ private void AssertProjectItemNameCount(ProjectInstance msbuildProject, string i
             Assert.Equal(count, itemGroup.Count());
         }
 
+        private SolutionFile ParseSolutionHelper(string solutionFileContents, bool useNewParser)
+        {
+            return useNewParser ? SolutionFile_NewParser_Tests.ParseSolutionHelper(solutionFileContents) :
+                SolutionFile_OldParser_Tests.ParseSolutionHelper(solutionFileContents);
+        }
+
         #endregion // Helper Functions
     }
 }
diff --git a/src/Build.UnitTests/Graph/GetCompatiblePlatformGraph_Tests.cs b/src/Build.UnitTests/Graph/GetCompatiblePlatformGraph_Tests.cs
index b941649ad74..d6344240f1a 100644
--- a/src/Build.UnitTests/Graph/GetCompatiblePlatformGraph_Tests.cs
+++ b/src/Build.UnitTests/Graph/GetCompatiblePlatformGraph_Tests.cs
@@ -402,14 +402,14 @@ public void SolutionWithoutAllConfigurations()
 
                 // Slashes here (and in the .slnf) are hardcoded as backslashes intentionally to support the common case.
                 TransientTestFile solutionFile = testEnvironment.CreateFile(folder, "SimpleProject.sln",
-                    @"
+                    """
                     Microsoft Visual Studio Solution File, Format Version 12.00
                     # Visual Studio Version 16
                     VisualStudioVersion = 16.0.29326.124
                     MinimumVisualStudioVersion = 10.0.40219.1
-                    Project(""{9A19103F-16F7-4668-BE54-9A1E7A4F7556}"") = ""Project1"", ""1\1\1.csproj"", ""{79B5EBA6-5D27-4976-BC31-14422245A59A}""
+                    Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Project1", "1\1\1.csproj", "{79B5EBA6-5D27-4976-BC31-14422245A59A}"
                     EndProject
-                    Project(""{9A19103F-16F7-4668-BE54-9A1E7A4F7556}"") = ""2"", ""2\2\2.proj"", ""{8EFCCA22-9D51-4268-90F7-A595E11FCB2D}""
+                    Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "2", "2\2\2.proj", "{8EFCCA22-9D51-4268-90F7-A595E11FCB2D}"
                     EndProject
                     Global
                         GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -434,7 +434,7 @@ public void SolutionWithoutAllConfigurations()
                             SolutionGuid = {DE7234EC-0C4D-4070-B66A-DCF1B4F0CFEF}
                         EndGlobalSection
                     EndGlobal
-                ");
+                    """);
 
                 ProjectCollection projectCollection = testEnvironment.CreateProjectCollection().Collection;
                 MockLogger logger = new();
diff --git a/src/Build.UnitTests/Graph/GraphLoadedFromSolution_tests.cs b/src/Build.UnitTests/Graph/GraphLoadedFromSolution_tests.cs
index 431ea412875..6d535479b1e 100644
--- a/src/Build.UnitTests/Graph/GraphLoadedFromSolution_tests.cs
+++ b/src/Build.UnitTests/Graph/GraphLoadedFromSolution_tests.cs
@@ -59,7 +59,8 @@ public void GraphConstructionFailsOnNonExistentSolution()
                     new ProjectGraph("nonExistent.sln");
                 });
 
-            exception.Message.ShouldContain("The project file could not be loaded. Could not find file");
+            exception.Message.ShouldContain("The project file could not be loaded.");
+            exception.Message.ShouldContain("Could not find file");
         }
 
         [Fact]
@@ -646,28 +647,6 @@ IEnumerable<ProjectItemInstance> GetIncomingEdgeItemsToNode(ProjectGraphNode nod
             }
         }
 
-        [Fact]
-        public void GraphConstructionShouldThrowOnMissingSolutionDependencies()
-        {
-            var solutionContents = SolutionFileBuilder.FromGraphEdges(
-                _env,
-                new Dictionary<int, int[]> { { 1, null }, { 2, null } },
-                new[] { ("1", new[] { Guid.NewGuid().ToString("B") }) }).BuildSolution();
-
-            var solutionFile = _env.CreateFile(
-                "solution.sln",
-                solutionContents)
-                .Path;
-
-            var exception = Should.Throw<InvalidProjectFileException>(
-                () =>
-                {
-                    new ProjectGraph(solutionFile);
-                });
-
-            exception.Message.ShouldContain("but a project with this GUID was not found in the .SLN file");
-        }
-
         private static bool IsSolutionItemReference(ProjectItemInstance edgeItem)
         {
             return edgeItem.ItemType == GraphBuilder.SolutionItemReference;
diff --git a/src/Build/Construction/Solution/SolutionFile.cs b/src/Build/Construction/Solution/SolutionFile.cs
index 983cd691d0d..909feaf74a6 100644
--- a/src/Build/Construction/Solution/SolutionFile.cs
+++ b/src/Build/Construction/Solution/SolutionFile.cs
@@ -193,7 +193,7 @@ internal int VisualStudioVersion
 
         internal bool UseNewParser => ShouldUseNewParser(_solutionFile);
 
-        internal static bool ShouldUseNewParser(string solutionFile) => FileUtilities.IsSolutionXFilename(solutionFile);
+        internal static bool ShouldUseNewParser(string solutionFile) => ChangeWaves.AreFeaturesEnabled(ChangeWaves.Wave17_14) || FileUtilities.IsSolutionXFilename(solutionFile);
 
         /// <summary>
         /// All projects in this solution, in the order they appeared in the solution file
@@ -221,6 +221,10 @@ internal string FullPath
 
             set
             {
+                if (ChangeWaves.AreFeaturesEnabled(ChangeWaves.Wave17_14) && string.IsNullOrEmpty(value))
+                {
+                    throw new ArgumentNullException(nameof(FullPath));
+                }
                 // Should already be canonicalized to a full path
                 ErrorUtilities.VerifyThrowInternalRooted(value);
                 // To reduce code duplication, this should be
diff --git a/src/Framework/ChangeWaves.cs b/src/Framework/ChangeWaves.cs
index 1d682c4fc75..8e58f93835c 100644
--- a/src/Framework/ChangeWaves.cs
+++ b/src/Framework/ChangeWaves.cs
@@ -27,7 +27,8 @@ internal static class ChangeWaves
     {
         internal static readonly Version Wave17_10 = new Version(17, 10);
         internal static readonly Version Wave17_12 = new Version(17, 12);
-        internal static readonly Version[] AllWaves = { Wave17_10, Wave17_12 };
+        internal static readonly Version Wave17_14 = new Version(17, 14);
+        internal static readonly Version[] AllWaves = { Wave17_10, Wave17_12, Wave17_14 };
 
         /// <summary>
         /// Special value indicating that all features behind all Change Waves should be enabled.