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Fixture parametrization overwrite each other. #4948
Description
- Include a detailed description of the bug or suggestion
I'm trying to parametrize a fixture using pytest_generate_tests(), with one
caveat: parametrization is different for each test function and depends on the
function name. I want a fixture to have a different value for different
test-cases.
When metafunc.parametrize('fixture_name', ...) is called with different
arguments, it somehow overwrites global parametrization for 'fixture_name', not
a per test-function parametrization.
-
pip listof the virtual environment you are using
Details
Package Version
----------------------------- ----------------------
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requests 2.9.1
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pytest and operating system versions
$ pytest --version
This is pytest version 4.3.1$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.6 LTS
Release: 16.04
Codename: xenial
` -
Minimal example if possible
test.py:
def test_one(heavy_fixture):
assert heavy_fixture == 'A'
def test_two(heavy_fixture):
assert heavy_fixture == 'B'conftest.py:
import pytest
def pytest_generate_tests(metafunc):
if metafunc.function.__name__ == 'test_one':
params = ['A']
else:
params = ['B']
metafunc.parametrize('heavy_fixture', params, scope="session", indirect=True)
@pytest.fixture
def heavy_fixture(request):
# Do a lot of heavy computation here
return request.paramresults:
$ pytest test.py
============================================================================ test session starts =============================================================================
platform linux -- Python 3.5.2, pytest-4.3.1, py-1.8.0, pluggy-0.9.0
rootdir: /home/afe/pytest3_fail, inifile:
collected 2 items
test.py .F [100%]
================================================================================== FAILURES ==================================================================================
________________________________________________________________________________ test_two[B] _________________________________________________________________________________
heavy_fixture = 'A'
def test_two(heavy_fixture):
> assert heavy_fixture == 'B'
E AssertionError: assert 'A' == 'B'
E - A
E + B
test.py:5: AssertionError
===================================================================== 1 failed, 1 passed in 0.02 seconds =====================================================================
Activity
[-]Fixtu[/-][+]Fixture parametrization overwrite each other.[/+]HunterMcGushion commentedon Mar 20, 2019
Hi, I may be misunderstanding what you're saying here
However, is there a reason you can't use
scope="function"in theconftest.pytest_generate_testsfunction's call tometafunc.parameterize?Here's the updated
conftest.py, which makes your tests pass:lexa commentedon Mar 20, 2019
The reason to use
score="session"is that the fixture is very computationally heavy and I want to minimize the number of times it is called.in the example below the fixture is called 4 times, while it is enough to call it only twice with
scope="session"bluetech commentedon Sep 12, 2020
This has been fixed by @aklajnert in #5798 (pytest 5.1.2).