Version Information

• TUnit: Issue observed in 0.50.x (e.g., 0.50.0, 0.50.1)
• Working as expected: 0.25.21
• OS: macOS 15.5 (arm64)
• .NET: 9.0
• IDE: Rider

Summary

In 0.25.21:

• IFirstTestInAssemblyEventReceiver was called exactly once per assembly.
• IFirstTestInClassEventReceiver was called exactly once per class.

In 0.50.x:

• The same code results in multiple calls for the same assembly/class.
• The call order can be interleaved with tests or occur after some tests have already run.

A gif comparing execution between 0.25.21 and 0.50.x will be attached.

Expected Behavior

• Assembly scope: IFirstTestInAssemblyEventReceiver should be called exactly once per assembly before any test in that assembly starts.
• Class scope: IFirstTestInClassEventReceiver should be called exactly once per class before any test in that class starts.

Actual Behavior (0.50.x)

• Multiple calls occur for the same assembly/class.
• Calls sometimes happen after tests in the same scope have started.
• The order between assembly-level and class-level first events is inconsistent.

Steps to Reproduce

1. Run with TUnit 0.25.21 → each event is called once and always before tests start.
2. Upgrade to TUnit 0.50.x → events are called multiple times or interleaved with test output.

Requests

1. Restore the exactly-once-per-scope guarantee in 0.50.x, or document conditions under which this guarantee does not hold.
2. Document execution order guarantees:
   • Assembly First → Class First → tests in that class.
3. Update documentation:
   • The current page lists the following interfaces, but does not describe
     IFirstTestInClassEventReceiver or IFirstTestInAssemblyEventReceiver:

     ITestRegisteredEventReceiver
     ITestStartEventReceiver
     ITestEndEventReceiver
     ILastTestInClassEventReceiver
     ILastTestInAssemblyEventReceiver
     ILastTestInTestSessionEventReceiver