pytest-harvest + pytest-steps: results_bag fixture is cross-step, how to get per-step?

[j-carson]

I have just started using your pytest extensions - they are wonderful, thank you!

I had a pytest-steps test with four steps, and each step saved the current value of a variable at the end of each step. The results_bag only had the value of the variable at the last step, and that value appeared in the row for the first step.

I fixed it by creating a per-step results bag fixture and using that in place of results_bag as the argument to my test. Is this the best way to get my desired behavior?

@pytest.fixture
@one_fixture_per_step
def step_bag(request):
    """pytest-harvest creates a results_bag per step so that it
    can calculate duration_ms per step, but results_bag seems
    to not be updated per step in my tests. This fixture
    explicitly grabs the current step's bag.

    Parameters
    ----------
    request: current running test object
        Fixture provided by pytest
    """
    return request.getfixturevalue("results_bag")

[smarie]

Thanks @j-carson ! This is a very nice way indeed to fix this issue. However if results_bag is not explicitly declared as a test dependency in your test function, request.getfixturevalue("results_bag") might not work.

Therefore, I would suggest the following, I suspect that it works too:

@pytest.fixture
@one_fixture_per_step
def step_bag(results_bag):
    return results_bag

Do you confirm ?

More generally I think that your proposal could make a great addition to pytest-steps. However it should be optional: if this fixture is provided by the plugin, and the user does not use it in any of its tests, the user should not need pytest-harvest to be installed. I think that with the above design, as long as "auto use" is not on, this is the pytest default behaviour. Do you confirm ?

[j-carson]

The shorter implementation of step_bag fixture works for me.

I think that with the above design, as long as "auto use" is not on, this is the pytest default behaviour. Do you confirm ?

I will need to write a test case to verify this second question.

[j-carson]

Wrote the test case for above: In a virtualenv with pytest-steps installed but not pytest-harvest, the above fixture will not cause an error if that fixture is not used by any test.

[smarie]

Cool ! Then it seems that all lights are green :) Would you like to propose a PR then ?

The fixture would need to live in module plugin.py and have at least one dedicated test. If you feel like updating the documentation markdown accordingly

• api_reference.md : probably add a subsection under https://smarie.github.io/python-pytest-steps/api_reference/#pytest-harvest-utility-methods

• index.md : probably add a subsection under https://smarie.github.io/python-pytest-steps/#3-usage-with-pytest-harvest)

(No need to test the case when the pytest-harvest plugin is not installed, this is a pytest mechanism and it wont change over time).

let me know !

[smarie]

Fixed by #46