Fixture as function argument in PyTest - Test Execution Trace

Test Overview

This test uses a pytest fixture to provide a sample list to the test function. It verifies that the fixture correctly supplies the data and that the test can access and assert the list contents.

Test Code - pytest

PyTest

import pytest

@pytest.fixture
def sample_list():
    return [1, 2, 3, 4, 5]


def test_sum_of_list(sample_list):
    total = sum(sample_list)
    assert total == 15
    assert len(sample_list) == 5

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test starts	pytest test runner initialized	-	PASS
2	pytest discovers the fixture 'sample_list'	Fixture 'sample_list' is registered and ready to be used	-	PASS
3	pytest calls test function 'test_sum_of_list' with 'sample_list' fixture as argument	The fixture function 'sample_list' is executed, returning [1, 2, 3, 4, 5]	-	PASS
4	Inside test, sum(sample_list) is calculated	sum is 15	assert total == 15	PASS
5	Inside test, length of sample_list is checked	length is 5	assert len(sample_list) == 5	PASS
6	Test completes successfully	Test passed with no errors	-	PASS

Failure Scenario

Failing Condition: The fixture 'sample_list' returns incorrect data or the assertion values are wrong

Execution Trace Quiz - 3 Questions

What does pytest do with the fixture 'sample_list' when running the test?

A It runs the fixture after the test completes

B It ignores the fixture and runs the test without any arguments

C It calls the fixture function and passes its return value as an argument to the test function

D It replaces the test function with the fixture function

Key Result

Using fixtures as function arguments in pytest helps keep tests clean and reusable by separating setup code from test logic.