Pytest Tips

Group test into categories with markers

You can use pytest markers to group tests into categories, e.g. unit, system, integration, etc.

You can mark tests, using pytest markers:

import pytest

# With following we mark all the tests in this module with `all` mark
pytestmark = [pytest.mark.all]

@pytest.mark.unit
def test_unit():
    assert True

@pytest.mark.system
def test_system():
    assert True

@pytest.mark.integration
def test_integration():
    assert True

Define markers in pytest.ini:

pytest.ini

[pytest]
markers =
    unit: mark test(s) as unit
    system: mark test(s) as system
    integration: mark test(s) as integration
    compat: compatibility test(s)
    all: all tests

To execute by default only unit tests, you can add to your pytest.ini:

pytest.ini

[pytest]
addopts =
    -m "unit"

$ pytest -vv

testing/test_markers.py::test_unit PASSED                                       [100%]

========================== 1 passed, 2 deselected in 0.09s ===========================

To execute only system and integration tests:

pytest -m "system or integration" -vv

testing/test_markers.py::test_system PASSED                                     [ 50%]
testing/test_markers.py::test_integration PASSED                                [100%]

========================== 2 passed, 1 deselected in 0.10s ===========================

To execute tests marked with all:

pytest -m "all" -vv

testing/test_markers.py::test_unit PASSED                                       [ 33%]
testing/test_markers.py::test_system PASSED                                     [ 66%]
testing/test_markers.py::test_integration PASSED                                [100%]

================================= 3 passed in 0.10s ==================================

You can also execute all tests by pasing empty argument to the markers expression:

pytest -m "" -vv

testing/test_markers.py::test_unit PASSED                                       [ 33%]
testing/test_markers.py::test_system PASSED                                     [ 66%]
testing/test_markers.py::test_integration PASSED                                [100%]

================================= 3 passed in 0.10s ==================================

Generate coverage report with every run

Add pytest coverage options to pytest.ini

# pytest.ini
[pytest]
addopts =
    --cov
    --cov-report=html
    --cov-report=term

doctest

Execute doctest tests with pytest

pytest --doctest-modules

Pass fixtures to doctest

pytest provides a doctest_namespace fixture which could be used to inject items into the namespace in which your doctests run.

The doctest_namespace fixture is a standard dict object. You can create an autouse fixture and inject necessary items from this fixture.

For more information, refer to the doctest_namespace fixture documentation.

For example:

import pytest

@pytest.fixture(autouse=True)
    def add_np(doctest_namespace):
        doctest_namespace["username"] = 'John'

"""
Let's see what is our username:

>>> username
'John'

"""