“Inconclusive” error in ReSharper unit test runner caused by “async void”

The ReSharper unit test runner doesn’t like test methods which are declared as “async void”.

Unfortunately you won’t get any compiler or intellisense warning to tell you. When trying to run the test in ResSharper unit test runner it will first get a blue question-mark icon and when you run it individually it will get the test result Inconclusive.

Example of an “conclusive” test result and a good one.

Code:

[TestMethod]
public async void This_Test_Will_Cause_Inconclusive_Message()
{
    // tests
}

[TestMethod]
public async Task This_Test_Will_Run_Ok()
{
 // tests
}