Python Testing with pytest

Using Fixtures for Test Data

Fixtures are a great place to store data to use for testing. You can return anything. Here’s a fixture returning a tuple of mixed type:

ch3/test_fixtures.py

@pytest.fixture()
def a_tuple():
    """Return something more interesting."""
    return (1, 'foo', None, {'bar': 23})


def test_a_tuple(a_tuple):
    """Demo the a_tuple fixture."""
    assert a_tuple[3]['bar'] == 32

Since test_a_tuple() should fail (23 != 32), we can see what happens when a test with a fixture fails:

$ cd /path/to/code/ch3
$ pytest test_fixtures.py::test_a_tuple
===================== test session starts ======================
collected 1 item

test_fixtures.py F


=========================== FAILURES ...