Source Generator Error when Overriding Inherited Tests

[nicolaskuster]

Description

When overriding/skipping an inherited test method in a derived class that uses [InheritsTests], the source generator fails with an ArgumentException due to duplicate hint names.

Error Message

CSC : warning CS8785: Generator 'TestMetadataGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'ArgumentException' with message 'The hintName 'TUnitSkipIssue_Tests_ImplementationATests_AdvancedFeature.g.cs' of the added source file must be unique within a generator. (Parameter 'hintName')'.

Use Case

Multiple implementations of the same interface/abstraction need to be tested. To avoid duplicating test code, an abstract base test class contains all test cases. Each implementation has a derived test class with [InheritsTests] to run the tests against that specific implementation.

Some implementations don't support all features, so certain tests need to be skipped in specific derived classes. Overriding the test method with [Skip] seems like a natural approach, but the build fails even when just overriding without [Skip].

Minimal Reproduction

public abstract class BaseServiceTests
{
    [Test]
    public async Task BasicFeature()
    {
        await Task.CompletedTask;
    }

    [Test]
    public async Task AdvancedFeature()
    {
        await Task.CompletedTask;
    }
}

[InheritsTests]
public class ImplementationATests : BaseServiceTests
{
    [Test]
    [Skip("Implementation A does not support advanced feature")]
    public new Task AdvancedFeature()
    {
        return Task.CompletedTask;
    }
}

(Note: The error occurs with or without the [Skip] attribute)

Expected Behavior

The source generator should recognize method hiding with the new keyword and only register the derived version for execution. This would allow either replacing the test implementation or skipping it with [Skip] (preferred).

Actual Behavior

The build fails because the generator attempts to create two files with the same hint name - one for the inherited test and one for the overridden test.

Environment

• TUnit Version: 1.0.78 (issue also occurs in 0.80.00)
• .NET Version: 10.0

Regression Information

This behavior worked correctly in version 0.79.0. The issue was introduced in version 0.80.0 and persists in version 1.0.78.

Question

Is using [InheritsTests] with method hiding the intended approach for skipping tests in specific implementations? If not, what is the recommended pattern for this scenario?

[thomhurst]

Hmm - Yeah I hadn't accounted for this scenario. If you make the base method virtual and then do a proper override in the derived class then does that work?

[nicolaskuster]

Hej @thomhurst , thanks a lot for your quick reply!
You’re absolutely right – with virtual and override, it already behaves as expected in version 1.0.78.
I’ve also tested version 1.1.10, and it now works also with the new keyword in the derived class.

Many thanks for the fast turnaround and for your great work on TUnit ❤️