p/analyzer-test/

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p/analyzer-test/

always learning | always growing

https://www.alwaysdeveloping.net/p/analyzer-test/

[Serenyrddraig]

I've had to learn how to write Analyzer/Codefix in the last couple of weeks. This set of articles is absolutely the most informative 'how to' (especially on writing unit tests) that I've found. I really struggled with how to setup complex unit tests prior to this discovery. Thank you.

[always-developing]

Thanks for the feedback, and I am glad it was of help to you!

[paul1956]

I am trying to write an Analyzer for WinForms which is working by I can't figure out how to get the test to understand System.Windows.Forms. From Your example I need to include it as a package but where do I get the package identities?
Is it as simple as

ReferenceAssemblies = new ReferenceAssemblies(
            "net6.0", 
            new PackageIdentity("System.Windows.Forms", "6.0.0")
    }

[paul1956]

This is what I came up with, but it doesn't work.

        Dim packageIdentity1 As New PackageIdentity("System.Windows.Forms.Ref", "6.0.0")
        Dim test As New Test With {
            .TestCode = source,
            .ReferenceAssemblies = New ReferenceAssemblies("net6.0", packageIdentity1, Path.Combine("ref", "net6.0"))
        }

[paul1956]

For those looking for a solution

        Dim test As New Test With {
            .TestCode = source,
            .ReferenceAssemblies = NetFramework.Net472.WindowsForms
        }

And you can select any framework by name.

[always-developing]

Glad you found a solution, and thank you for sharing it here for everyone to benefit from in future! Appreciate it.

[Sugam011]

I am facing this issue https://stackoverflow.com/questions/71683935/c-sharp-code-analyzer-test-is-not-working-but-test-is-correct

[Sugam011]

I have also try unit test like enhanced unit test and according to one of answer provided on above link that PR is already merged so I guess testing libraries are already updated if not kindly help me with how to do according to that answer or if there is any other way anyone know. It would be great help. Thanks.

[suntereo]

Thanks for this series. Very helpful!

[f3]

Nicely done. Question (if you don't mind):
How can we "pull in" configuration options in the unit test.
For example, I have an analyzer that counts lines of code in a class and emits a diagnostic if the LOC is above a certain threshold. This threshold has a default value, but can be configured in the .editorconfig. I have a test that can exercise the default value, but how can I write tests that exercise a value that has been overridden in the configuration?

[always-developing]

Hi - you basically have two options

1. Use the "AdditionalFiles" mechanism. In your analyzer you can check if the .editorconfig has been included as an additional file (in the same code, I did a similar thing with appsettings.json

var editConfig= context.Options.AdditionalFiles.First(x => x.Path.EndsWith(".editorconfig", StringComparison.OrdinalIgnoreCase));

And then in your test you can mock it by doing:

analyzerTest.TestState.AdditionalFiles.Add((" .editorconfig", "Your file contents"));

The BIG disadvantage of this approach, is that the .editorconfig has to have the "Build Action" set to C# analyzer additional file.

2. Have a look here: https://github.com/mavasani/roslyn-analyzers/blob/master/src/PublicApiAnalyzers/Core/Analyzers/DeclarePublicApiAnalyzer.cs. I've not tested this approach, but it appears to be doing what you require (getting values from the editor config)

Hope this helps!

[BrainCrumbz]

Hi. Thanks for sharing your experience here, still useful as of 2024. Searching through various scenarios I could not find one we're trying to make it work, here it is:

A generator uses a marker attribute (with internal access). The marker attribute source itself is generated, so the project using the generator has that, but another project has not. When text containing source code (like var test = @"...") under test refers to the attribute, the context created by CSharpAnalyzerTest of course cannot find that attribute and so 1) it cannot compile, ok, whatever, but 2) analyzer under test will not work because will fail detecting the marker attribute.

Using a marker attribute with generator seems to be quite common. And generating attribute itself was seen in other blog posts.

Is there a way to run some generator when testing through CSharpAnalyzerTest (or CSharpCodeFixTest)?

Thanks!

[BrainCrumbz]

Oh well, it seems there's a simple solution: just add the source code text of the attribute together with the source code under test. E.g.

var test = @"...";
var attrSource = @"..."
[...]
Sources = { test, attrSource },