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Fixed in 1.1.10



Found in [Package]


Issue ID




[TestRunner] "EditMode test can only yield null" error is thrown when two or more yield returns are used in one test

Package: DS - Unity Test Framework


Further investigation showed that it is not the nested-IEnumerator situation that doesn't work, but the nested-Ienumerator+AsyncOperation that is not handled as an AsyncOperation in the right place/time. The solution introduced in the PR, works for this case but introduces thread-related problems in other cases. Example AsyncProgressBar.ProgresTests.SynchronousProtectionInMultithreaded()

How to reproduce:
1. Open the attached "case_1171956" project
2. Go to Window -> General -> Test Runner
3. Run all tests

Expected result: Both tests will pass
Actual result: Only test with one yield return passes

Reproducible with: 2017.4.31f1, 2018.4.5f1, 2019.1.13f1, 2019.2.0f1, 2019.3.0a11

Full error message:
EditMode test can only yield null

Additional notes:
1. This issue occurs only in tests. Calling two or more yield returns in MonoBehavior script works as expected

Comments (1)

  1. barbarbarian

    Mar 14, 2023 01:38

    Multiple yield returns in a single [UnitTest] works for me. However, I did get this error when I was trying to run my async call with a yield return. Make sure you are only using yield return with a method of type IEnumerator or if you are trying to running a method that is async but not IEnumerator (so like a task), trying using AsIEnumerator() - that is: myAsyncTaskMethod.AsIEnumerator().

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