Async test methods in NUnit 3.x must return either Task if no value is returned, or Task<T> if a value of type T is returned. Below are two situations where async tests will not be working correctly.
[Test]// Warning: Async test method is voidpublicasyncvoidTest1(){// do somethingawait Task.CompletedTask;}[Test]// Warning: NUnit 3.10 does not support ValueTaskpublicasyncValueTask<int>Test2(){// do somethingreturnawait Task.FromResult(100);}
In both situations you need to rewrite test methods so that they return either Task or Task<T>.