Issue 26323: Add assert_called() and assert_called_once() methods for mock objects

Would a patch for adding a assert_called() method to mocked objects be welcome for inclusion? We do have a assert_not_called() method, so I think this may be a good idea. Please let me know and I will work on it.

I agree this would be useful. "assert themock.called" (or self.assertTrue) works, but always trips me up.

Please take a look at the attached patch.

Fixed the test name

If we go into this direction, I suggest to add *two* methods:

* assert_called(): called at least once
* assert_called_once(): called exactly once

I would be more consitent with the existing API:

https://docs.python.org/dev/library/unittest.mock.html#unittest.mock.Mock.assert_not_called

https://docs.python.org/dev/library/unittest.mock.html#unittest.mock.Mock.assert_called_with

https://docs.python.org/dev/library/unittest.mock.html#unittest.mock.Mock.assert_called_once_with

> I would be more consitent with the existing API:

Hum, I'm not sure that I was clear.

If we only add assert_called() (without assert_called_once()), users may use assert_called() to check if a function is called exactly once which would be a mistake.

Thanks for your comments. I am +1 to those additions and would be happy to update the patch. Let me know if I should go ahead.

Go ahead and update the patch for assert_called_once and related tests.

Added assert_call_once()

I reviewed your patch.

Thanks for the review. Updated patch addressing the comments.

Updated patch

Can you please also document your changes in Doc/library/unittest.mock.rst? You will have to use ".. versionadded:: 3.6" in the doc of new functions.

You may also document directly the news functions in Doc/whatsnew/3.6.rst. It looks like you have to add a new "unittest" section in "Improved Modules".

Updated patch with docs and addressed review comments.

@haypo : Just a reminder request to please view the updated patch.

The latest patch looks good to me, but I would prefer to have a review of the maintainer of the unittest.mock module (Michael Ford, voidspace?), or at least a second core developer.

@Robert: Would you mind reviewing the latest patch please?

Updated patch

There have been persistent calls for an "assert_called" method over the lifetime of mock. In the past I've rejected them because you can easily get it by asserting the call count is non-zero and I want to avoid the proliferation of a thousand assert methods. The demand is certainly consistent, so it would seem that people feel there is a use case.

> In the past I've rejected them because you can easily get it by asserting the call count is non-zero and I want to avoid the proliferation of a thousand assert methods

Yeah, I understand that.

IMHO having to check if a function was called is a common need. Mock
has already assert_not_called() for example.

I like the detection of spelling typos for methods starting with assert_ :-)

Thanks Michael, so looks like we are all set for merging this?

Yes, this can go in.

New changeset bd75f8d34f97 by Victor Stinner in branch 'default':
Add Mock.assert_called()
https://hg.python.org/cpython/rev/bd75f8d34f97

> Yes, this can go in.

Cool. I pushed the latest patch of Amit Saha. I just modified assert_call() doc to add "at least once".

Thanks Amit for your contribution!

Thank you Victor.

messages: + msg260656

messages: + msg260487

messages: + msg260454

messages: + msg260432

messages: + msg260409
versions: + Python 3.6

messages: + msg260144