Invoke the test function, passing (), the unit value, to the the test function.
Invoke the test function, passing (), the unit value, to the the test function.
To enable stacking of traits that define withFixture(NoArgTest), this method does not
invoke the test function directly. Instead, it delegates responsibility for invoking the test function
to withFixture(NoArgTest).
the OneArgTest to invoke, passing in the unit value