I'm mocking a method that returns a Promise:

myMock.setup(x => x.method()).returns(() => Promise.reject(new Error("blah")));

I noticed that the "returns" implementation is executed twice even if "method" is called only once on the mock.
This should not be a problem normally, the issue is that in this particular case, the test runner is failing because it detects an unhandled promise rejection.

Is this a known behavior?