Pytest: Order of decorators type: question

[sshevlyagin]

• pytest 3.6.2, python 3.6.1, OS X 10.3.15

I ran into a very cryptic error in pytest, after adding a '@pytest.mark.parametrize' decorator the test started throwing the following error:

ValueError: <function ... at ...> uses no argument 'parameters'

I found the source of the error here

Here's what the signature of my function looks like (simplified):

@patch('dog')
@pytest.mark.parametrize('foo,bar', test_data)
def test_update_activity_details_trainer_and_gear(self, foo, bar, dog):

Turns out the order of decorators in pytest matters

@pytest.mark.parametrize('foo,bar', test_data)
@patch('dog')
def test_update_activity_details_trainer_and_gear(self, dog, foo, bar):

Changing the order removed the error.

Question - could there be a more helpful error for n00bs like me?

Posted in stackoverflow as well

[RonnyPfannschmidt]

its not clear what to do there, imho mock,patch support should be deprecated as its unclean and doable much better these days (we shoul djust have a marker for patchings and be done with the funky mess the patch decorator introduces

[pytestbot]

GitMate.io thinks possibly related issues are https://github.com/pytest-dev/pytest/issues/3581 (only decorator), https://github.com/pytest-dev/pytest/issues/129 (Test functions with decorators are collected in wrong order), https://github.com/pytest-dev/pytest/issues/2861 (Question re: order of execution of test fixtures), https://github.com/pytest-dev/pytest/issues/3342 (Support for static typing), and https://github.com/pytest-dev/pytest/issues/3601 ((question) Cleaning up from parameter generation).

[sshevlyagin]

@RonnyPfannschmidt - thanks for the quick response, where should I look for how to do it better? Very curious to learn.

[RonnyPfannschmidt]

pytest-mock is a starting point, but it currently has no marker replacing the patch decorator

[sshevlyagin]

Appreciated, I'll check it out.