Omitting to_return_value changes expectation checks

[levidobson]

See the following examples. In both cases the mocked function gets called by the tested code.

self.mock_callable(
    mock_service, "func"
).for_call(expected_request).to_return_value(None).and_assert_called_once()
# passes, all good

self.mock_callable(
    mock_service, "func"
).for_call(expected_request).and_assert_called_once()
# error: UnexpectedCallReceived: <StrictMock ...>, 'function_name': Excepted not to be called!

I'm not sure if omitting to_return_value should be allowed or not, but it looks like the error message is a bit detached from the expectations anyway. The error message says Excepted not to be called! when clearly I have an .and_assert_called_once().

(Btw I just noticed there is a typo in the error message Excepted -> Expected.)

[fornellas]

The error message is indeed misleading, but it is doing the right thing. Looking at

self.mock_callable(
    mock_service, "func"
).for_call(expected_request).and_assert_called_once()

you are telling the mock to accept a specific call, but not telling it what to do when this call is made. In this case, using and_assert_called_once() makes little sense, as the test would never pass, as the call can never succeed.

I just put #85 that makes this case a ValueError:

    1) ValueError: You must first define a behavior. Eg: self.mock_callable(target, 'func').to_return_value(value).and_assert_called_exactly(times)