How to use roslynator packages for custom analysers

[nathanpovo]

How possible it is to use the roslynator packages to write your own custom packages?

The docs mention that some of the packages are available for developers to be able to write and test their custom analysers

roslynator/README.md

Lines 50 to 63 in 32c1804

	## Testing Framework
	- Roslynator Testing Framework can be used for unit testing of analyzers, refactorings and code fixes.
	- Framework is distributed as NuGet [package](https://www.nuget.org/packages/Roslynator.Testing.CSharp.Xunit).  [](https://www.nuget.org/packages/Roslynator.Testing.CSharp.Xunit)
	- Learn how to use the framework from actual usages in Roslynator repo:
	- Tests of analyzers are [here](https://github.com/dotnet/roslynator/tree/main/src/Tests/Analyzers.Tests), [here](https://github.com/dotnet/roslynator/tree/main/src/Tests/CodeAnalysis.Analyzers.Tests) and [here](https://github.com/dotnet/roslynator/tree/main/src/Tests/Formatting.Analyzers.Tests)
	- Tests of refactorings are [here](https://github.com/dotnet/roslynator/tree/main/src/Tests/Refactorings.Tests)
	- Tests of fixes of compiler diagnostics are [here](https://github.com/dotnet/roslynator/tree/main/src/Tests/CodeFixes.Tests)
	## Client Libraries
	- Roslynator client libraries are meant be used for development of your own analyzers/refactorings.
	- It does not contain any analyzers/refactorings itself.
	- See [reference](https://josefpihrt.github.io/docs/roslynator/ref).

However, I could not find out how to actually use them. The documentation does not go into detail on this.

The unit tests in the solution use a number of internal types (making it impossible for me to use them in a custom roslyn analyser). There are also a number of auto-generated c# classes in this repo (that are referenced by the unit tests), but there is no info on how these were generated.

[josefpihrt]

Hi,

Thank you for the question. I would separate this issue into two parts:

.NET API extending Roslyn API (packages Roslynator.Core etc.)

I added this page about how to use .NET API in a custom analyzer package.

Usage of testing framework

I prepared PR that makes lot of types public which makes the development of unit test easier.

And here is PR that updates docs.

Any comments of the PRs are welcome.

Nevertheless, technically this PR introduces a breaking change which mean that it should be merged when next major version is released which is usually when next major version of Roslyn is released. I have to think about it whether to merge it earlier.

The good news is that there very simple workaround: just copy project "Tests.Common" to your project and use it. Then the development experience will be virtually the same as with the PR merged.

[nathanpovo]

Thank you for getting back to me so quickly!

Regarding this section of the docs https://josefpihrt.github.io/docs/roslynator/how-to-use-net-api#analyzer-package-configuration, is that only relevant for when the analyser is being packaged for nuget? I wouldn't need to worry about this while developing locally, right?

[josefpihrt]

Correct.

[nathanpovo]

There are also a number of auto-generated c# classes in this repo (that are referenced by the unit tests), but there is no info on how these were generated.

Any info on this?

These are the files I am referring to

https://github.com/dotnet/roslynator/blob/32c1804bbdef8b832f18debb59072bd1645d34fb/src/Analyzers/CSharp/DiagnosticRules.Generated.cs

https://github.com/dotnet/roslynator/blob/32c1804bbdef8b832f18debb59072bd1645d34fb/src/Analyzers/CSharp/DiagnosticIdentifiers.Generated.cs

The (new) docs on unit testing also reference them

https://github.com/josefpihrt/josefpihrt.github.io/blob/f39502ef76fd6a915f5914befc1cf2c8b0ef0bed/docs/roslynator/analyzers-testing.md?plain=1#L26

[josefpihrt]

It' not important that the classes are auto-generated.

Important fact is that when you want to test some analyzer you have to include DiagnosticDescriptor in your unit test class. It's up you where you define DiagnosticDescriptor for your analyzer.

DiagnosticIdentifiers contains just list of diagnostic IDs it's not necessary to include them in the unit test. In fact, diagnostic ID is part of DiagnosticDescriptor.

The (new) docs on unit testing also reference them

I will remove it to avoid any further confusion.

[josefpihrt]

@nathanpovo Roslynator 4.6.0 has been released. It contains changes from #1214

Documentation has been updated accordingly https://josefpihrt.github.io/docs/roslynator/testing