Initial unit tests (#6)

* added test project

* added code coverage tooling

Per directions on https://seankilleen.com/2024/03/beautiful-net-test-reports-using-github-actions/

* only run code coverage reporting on Linux

* basic sanity checks for NonZeroUInt32

* added topic validator

.github/workflows/pr_validation.yaml

@@ -14,6 +14,8 @@ on:
 
 jobs:
   test:
+    # Permissions this GitHub Action needs for other things in GitHub
+    permissions: write-all
     name: Test-${{matrix.os}}
     runs-on: ${{matrix.os}}
 
@@ -39,4 +41,52 @@ jobs:
         run: dotnet build -c Release
 
       - name: "dotnet test"
-        run: dotnet test -c Release
+        run: dotnet test --configuration Release --verbosity normal --logger trx --collect:"XPlat Code Coverage"
+
+      - name: Combine Coverage Reports
+        if: runner.os == 'Linux'
+        uses: danielpalme/[email protected]
+        with:
+          reports: "**/*.cobertura.xml"
+          targetdir: "${{ github.workspace }}"
+          reporttypes: "Cobertura"
+          verbosity: "Info"
+          title: "Code Coverage"
+          tag: "${{ github.run_number }}_${{ github.run_id }}"
+          customSettings: ""
+          toolpath: "reportgeneratortool"
+
+      - name: Publish Code Coverage Report
+        if: runner.os == 'Linux'
+        uses: irongut/[email protected]
+        with:
+          filename: "Cobertura.xml"
+          badge: true
+          fail_below_min: false
+          format: markdown
+          hide_branch_rate: false
+          hide_complexity: false
+          indicators: true
+          output: both
+          thresholds: "10 30"
+
+      - name: Add Coverage PR Comment
+        if: github.event_name == 'pull_request' && runner.os == 'Linux'
+        uses: marocchino/sticky-pull-request-comment@v2
+        with:
+          recreate: true
+          path: code-coverage-results.md
+
+      - name: Upload Test Result Files
+        if: runner.os == 'Linux'
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-results
+          path: ${{ github.workspace }}/**/TestResults/**/*
+          retention-days: 5
+
+      - name: Publish Test Results
+        if: always() && runner.os == 'Linux'
+        uses: EnricoMi/[email protected]
+        with:
+          trx_files: "${{ github.workspace }}/**/*.trx"

Directory.Packages.props

@@ -7,4 +7,15 @@
   <ItemGroup>
     <PackageVersion Include="Akka.Hosting" Version="1.5.18" />
   </ItemGroup>
+
+  <!-- Test Package Versions -->
+  <ItemGroup>
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+    <PackageVersion Include="xunit" Version="2.7.0" />
+    <PackageVersion Include="xunit.runner.visualstudio" Version="2.5.4" />
+    <PackageVersion Include="FluentAssertions" Version="6.12.0" />
+    <PackageVersion Include="coverlet.collector" Version="3.2.0" />
+    <PackageVersion Include="Verify.Xunit" Version="17.10.2" />
+    <PackageVersion Include="Verify.DiffPlex" Version="1.3.0" />
+  </ItemGroup>
 </Project>

TurboMqtt.sln

@@ -5,6 +5,16 @@ VisualStudioVersion = 17.0.31903.59
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TurboMqtt.Core", "src\TurboMqtt.Core\TurboMqtt.Core.csproj", "{BE905781-3D96-44F5-A230-E06FD5213C1C}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TurboMqtt.Core.Tests", "tests\TurboMqtt.Core.Tests\TurboMqtt.Core.Tests.csproj", "{8090B5F4-3C72-451E-8EC1-F73F8296A765}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "build", "build", "{B3AABB6F-ACB0-4CFB-A17B-6B2189369139}"
+	ProjectSection(SolutionItems) = preProject
+		Directory.Build.props = Directory.Build.props
+		Directory.Packages.props = Directory.Packages.props
+		global.json = global.json
+		nuget.config = nuget.config
+	EndProjectSection
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -18,5 +28,9 @@ Global
 		{BE905781-3D96-44F5-A230-E06FD5213C1C}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{BE905781-3D96-44F5-A230-E06FD5213C1C}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{BE905781-3D96-44F5-A230-E06FD5213C1C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{8090B5F4-3C72-451E-8EC1-F73F8296A765}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8090B5F4-3C72-451E-8EC1-F73F8296A765}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8090B5F4-3C72-451E-8EC1-F73F8296A765}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8090B5F4-3C72-451E-8EC1-F73F8296A765}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 EndGlobal

src/TurboMqtt.Core/MqttTopicValidator.cs

@@ -0,0 +1,77 @@
+// -----------------------------------------------------------------------
+// <copyright file="MqttTopicValidator.cs" company="Petabridge, LLC">
+//      Copyright (C) 2024 - 2024 Petabridge, LLC <https://petabridge.com>
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace TurboMqtt.Core;
+
+public static class MqttTopicValidator
+{
+    /// <summary>
+    /// Validates an MQTT topic ID for publishing or subscribing.
+    /// </summary>
+    /// <param name="topic">The topic to validate.</param>
+    /// <param name="forSubscription">Specifies whether the validation is for subscribing (true) or publishing (false).</param>
+    /// <returns>A tuple indicating whether the topic is valid and an error message if it is not.</returns>
+    public static (bool IsValid, string ErrorMessage) ValidateTopic(string topic, bool forSubscription = true)
+    {
+        // Check if the topic is empty
+        if (string.IsNullOrEmpty(topic))
+        {
+            return (false, "Topic must not be empty.");
+        }
+
+        // Check if the topic contains the null character
+        if (topic.Contains('\0'))
+        {
+            return (false, "Topic must not contain null characters.");
+        }
+
+        // Check for invalid wildcard usage if for publishing
+        if (!forSubscription)
+        {
+            if (topic.Contains('+') || topic.Contains('#'))
+            {
+                return (false, "Wildcards ('+' and '#') are not allowed in topics for publishing.");
+            }
+        }
+
+        // Validate wildcards for subscription
+        if (forSubscription)
+        {
+            // Validate '+'
+            int indexOfPlus = topic.IndexOf('+');
+            while (indexOfPlus != -1)
+            {
+                if ((indexOfPlus > 0 && topic[indexOfPlus - 1] != '/') ||
+                    (indexOfPlus < topic.Length - 1 && topic[indexOfPlus + 1] != '/'))
+                {
+                    return (false, "Single-level wildcard '+' must be located between slashes or at the beginning/end of the topic.");
+                }
+                indexOfPlus = topic.IndexOf('+', indexOfPlus + 1);
+            }
+
+            // Validate '#'
+            if (topic.Contains('#') && !topic.EndsWith("/#") && !topic.Equals("#"))
+            {
+                return (false, "Multi-level wildcard '#' must be at the end of the topic or after a '/'.");
+            }
+        }
+
+        // Check for forbidden use of '$' at the beginning by clients
+        if (topic.StartsWith($"$"))
+        {
+            return (false, "Topics starting with '$' are reserved and should not be used by clients for publishing.");
+        }
+
+        // Optional: Check for excessive length (implementation-specific limit)
+        if (topic.Length > 65535) // Example maximum length
+        {
+            return (false, "Topic exceeds the maximum length allowed.");
+        }
+
+        // If all checks pass
+        return (true, "Topic is valid.");
+    }
+}

src/TurboMqtt.Core/Properties/Friends.cs

@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("TurboMqtt.Core.Tests")]

tests/TurboMqtt.Core.Tests/GlobalUsings.cs

@@ -0,0 +1,2 @@
+global using Xunit;
+global using FluentAssertions;

tests/TurboMqtt.Core.Tests/MqttTopicValidatorSpecs.cs

@@ -0,0 +1,51 @@
+// -----------------------------------------------------------------------
+// <copyright file="MqttTopicValidatorSpecs.cs" company="Petabridge, LLC">
+//      Copyright (C) 2024 - 2024 Petabridge, LLC <https://petabridge.com>
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace TurboMqtt.Core.Tests;
+
+public class MqttTopicValidatorSpecs
+{
+    public static readonly TheoryData<string> FailureCases = new TheoryData<string>(
+
+        "foo/bar+", // invalid wildcard position
+        "home/kit+chen/light", // invalid wildcard position
+        "home/+/kitchen+", // invalid wildcard position
+        "home+kitchen/light", // invalid wildcard position
+
+        // generate some invalid uses of the '#' wildcard
+        "foo/#/bar", // invalid wildcard position
+
+        // generate some invalid uses of the '$' characterq
+        "$foo/bar", // invalid use of '$' character
+
+        // generate some invalid uses of the null character
+        "foo\0bar" // invalid use of null character
+    );
+
+    [Theory]
+    [MemberData(nameof(FailureCases))]
+    public void ShouldFailValidationForTopicSubscription(string topic)
+    {
+        var result = MqttTopicValidator.ValidateTopic(topic, true);
+        result.IsValid.Should().BeFalse();
+    }
+
+    public static readonly TheoryData<string> SuccessCases = new TheoryData<string>(
+        "home/kitchen/light",
+        "home/kitchen/temperature",
+        "home/kitchen/humidity",
+        "home/+/pressure",
+        "home/kitchen/pressure/#"
+    );
+
+    [Theory]
+    [MemberData(nameof(SuccessCases))]
+    public void ShouldPassValidationForTopicSubscription(string topic)
+    {
+        var result = MqttTopicValidator.ValidateTopic(topic, true);
+        result.IsValid.Should().BeTrue();
+    }
+}

tests/TurboMqtt.Core.Tests/NonZeroUintTests.cs

@@ -0,0 +1,17 @@
+namespace TurboMqtt.Core.Tests;
+
+public class NonZeroUintTests
+{
+    [Fact]
+    public void ShouldFailOnZero()
+    {
+        Assert.Throws<ArgumentOutOfRangeException>(() => new NonZeroUInt32(0));
+    }
+
+    [Fact]
+    public void ShouldSucceedOnNonZero()
+    {
+        var nonZero = new NonZeroUInt32(1);
+        Assert.Equal(1u, nonZero.Value);
+    }
+}

tests/TurboMqtt.Core.Tests/TurboMqtt.Core.Tests.csproj

@@ -0,0 +1,30 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net8.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+
+        <IsPackable>false</IsPackable>
+        <IsTestProject>true</IsTestProject>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Microsoft.NET.Test.Sdk"/>
+        <PackageReference Include="xunit"/>
+        <PackageReference Include="xunit.runner.visualstudio">
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+            <PrivateAssets>all</PrivateAssets>
+        </PackageReference>
+        <PackageReference Include="coverlet.collector">
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+            <PrivateAssets>all</PrivateAssets>
+        </PackageReference>
+        <PackageReference Include="FluentAssertions"/>
+    </ItemGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\..\src\TurboMqtt.Core\TurboMqtt.Core.csproj" />
+    </ItemGroup>
+
+</Project>