Fixture dependencies (fixture using fixture) in PyTest - Test Execution Trace

Test Overview

This test demonstrates how one pytest fixture can use another fixture as a dependency. It verifies that the dependent fixture correctly receives and uses the data from the base fixture.

Test Code - pytest

PyTest

import pytest

@pytest.fixture
def base_data():
    return 10

@pytest.fixture
def dependent_data(base_data):
    return base_data * 2

def test_dependent_fixture(dependent_data):
    assert dependent_data == 20

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test starts	pytest test runner initialized	-	PASS
2	pytest discovers test_dependent_fixture and its fixture dependencies	Test function and fixtures recognized	-	PASS
3	pytest calls base_data fixture	base_data fixture returns 10	-	PASS
4	pytest calls dependent_data fixture with base_data=10	dependent_data fixture returns 20	-	PASS
5	pytest runs test_dependent_fixture with dependent_data=20	Test function executes assertion	assert dependent_data == 20	PASS
6	Test ends	All assertions passed	-	PASS

Failure Scenario

Failing Condition: dependent_data fixture returns incorrect value (not double base_data)

Execution Trace Quiz - 3 Questions

Which fixture provides the initial value used by the dependent fixture?

A dependent_data

B base_data

C test_dependent_fixture

D pytest

Key Result

Using fixture dependencies in pytest helps organize test setup by reusing common data or setup steps, making tests cleaner and easier to maintain.