Use the pytest_collection_modifyitems hook to select only tests that use a certain fixture
The hook-based plugin architecture of pytest empowers you to heavily customize the test runners behavior. In this particular case we'll make use of the pytest_collection_modifyitems hook. It is called after collection has been performed and hence provides access to the actual test items - objects which represent a single test.
Hooks have access to pytest's builtin fixtures such as config. We case use it to explicitly run a hook for deselecting test items, namely config.hook.pytest_deselected.
Watch out! This hook does not return the test items. Instead you want to populate the given list as needed: items[:] = selected_items
Pytests modular design allows you to re-use fixtures. The fixturenames attribute of a test item not only holds the fixtures which are specified in its signature but also the ones that are used implicitly.
# conftest.py
def pytest_collection_modifyitems(items, config):
selected_items = []
deselected_items = []
for item in items:
if 'new_fixture' in getattr(item, 'fixturenames', ()):
selected_items.append(item)
else:
deselected_items.append(item)
config.hook.pytest_deselected(items=deselected_items)
items[:] = selected_items
# test_foobar.py
import pytest
@pytest.fixture
def new_fixture():
return 'foobar'
@pytest.fixture
def another_fixture(new_fixture):
return 'foobar'
def test_abc(new_fixture):
assert True
def test_def(another_fixture):
assert True
def test_that_does_not_use_fixture():
assert False
$ py.test -v
============================= test session starts ==============================
platform darwin -- Python 3.5.0, pytest-2.8.7, py-1.4.31, pluggy-0.3.1
collected 3 items
test_foobar.py::test_abc PASSED
test_foobar.py::test_def PASSED
==================== 2 passed, 1 deselected in 0.01 seconds ====================
COMMENTS