Python Testing with pytest

Randomizing Test Order

Generally we’d like each of our tests to be able to run independently of all other tests. Having independent tests allows for easy debugging if something ever fails. If test order inadvertently depends on the state of the system being tested, that independence is broken. One common way to test for order independence is to randomize the test run order.

The pytest-randomly plugin is excellent randomizing test order. It also randomizes the seed value for other random tools like Faker and Factory Boy. Let’s try it out on a couple simple test files:

ch14/random/test_a.py

def test_one():
    pass


def test_two():
    pass

ch14/random/test_b.py

def test_three():
    pass


def test_four():
    pass

If we ...