Chain Fixtures Requests

Introduction to Testing in Python

Alexander Levin

Data Scientist

What is a chain request

Chain fixtures requests - a pytest feature, that allows a fixture to use another fixture
Creates a composition of fixtures

fixture calls other fixture

Chain fixtures requests help to:

When it can be useful:

# Fixture that is requested by the other fixture
@pytest.fixture
def setup_data():
    return "I am a fixture!"

# Fixture that is requested by the test function
@pytest.fixture
def process_data(setup_data):
    return setup_data.upper()

# The test function
def test_process_data(process_data):
    assert process_data == "I AM A FIXTURE!"

# Fixture requesting other fixture
@pytest.fixture
def process_data(setup_data):
    return setup_data.upper()

Chain fixture requests - is a feature that allows a fixture to use another fixture (creating fixture compositions)
It helps to divide the code by functions and keep it modular
Example use case: the steps of data pipeline
To use chain fixture requests pass the fixture name to the other fixture signature

Introduction to Testing in Python