CODEWITHSUNDEEP
pythonpytestfixtures
Matt Giltaji
Matt Giltaji

Reputation: 318

AttributeError when using request.function in pytest yield fixture

I have several pytest test cases that need nearly identical setup, so I would like to have them reuse a fixture to keep things DRY. The setup involves creating a new ticket in an external ticket tracking system, then the test cases interact with the ticket based on the data, and finally the fixture cleans up by closing out the ticket. The challenge here is that each test case needs slightly different data to be prepped in the ticket.

Each test case has different calls and different assertions, so I can't combine them all into a single parametrized test case with a single test fixture. Parametrizing the the fixture itself would result in every test case running every permutation of the fixture data, which ends up with a lot of irrelevant test failures.

What I would like to do is set a variable in the test case, then have the fixture use that variable to set up the test data when creating the ticket. I've tried to use request.function as specified in the pytest fixture docs but I keep getting:

=================================== ERRORS ===================================
    ____________________ ERROR at setup of TestMCVE.test_stuff ___________________

request = <SubRequest 'ticket' for <Function 'test_stuff'>>

    @pytest.yield_fixture
    def ticket(request):
>       ticket_summary = getattr(request.function, "summary")
E       AttributeError: 'function' object has no attribute 'summary'

tests\test_mcve.py:11: AttributeError

My code is:

import pytest


def ticket_system_api(summary):
    # stub for MCVE purposes
    return summary


@pytest.yield_fixture
def ticket(request):
    ticket_summary = getattr(request.function, "summary")
    new_ticket = ticket_system_api(summary=ticket_summary)
    yield new_ticket


class TestMCVE:
    def test_stuff(self, ticket):
        summary = 'xyz'
        # do real things here, except MCVE
        assert 'xyz' == ticket

I've tried using request.node instead of request.function as well as binding the summary variable per this answer, changing summary = 'xyz' to test_stuff.summary = 'xyz' but these still fail with the same AttributeError.

How can I pass the function level data to the fixture?

Upvotes: 1

Views: 2752

Answers (1)

imiric
imiric

Reputation: 9030

You can accomplish this with indirect parametrization. The API (and the documentation) could be friendlier, but the functionality you want is there.

Your example was very close, and minor tweaks were needed. Take a look:

import pytest


def ticket_system_api(summary):
    # stub for MCVE purposes
    return summary


@pytest.fixture
def ticket(request):
    # NOTE: This will raise `AttributeError` if the fixture
    # doesn't receive a parameter.
    ticket_summary = request.param
    new_ticket = ticket_system_api(summary=ticket_summary)
    return new_ticket


class TestMCVE:
    @pytest.mark.parametrize('ticket', ('abc',), indirect=True)
    def test_abc(self, ticket):
        # do real things here, except MCVE
        assert ticket == 'abc'

    @pytest.mark.parametrize('ticket', ('xyz',), indirect=True)
    def test_xyz(self, ticket):
        # do real things here, except MCVE
        assert ticket == 'xyz'

Upvotes: 2

Related Questions