Fixture scope (function, class, module, session) in PyTest - Test Execution Trace

Test Overview

This test demonstrates how pytest fixtures with different scopes (function, class, module, session) are set up and used. It verifies that fixtures are created and destroyed according to their scope during test execution.

Test Code - pytest

PyTest

import pytest

@pytest.fixture(scope="function")
def func_scope():
    print("Setup function scope")
    yield
    print("Teardown function scope")

@pytest.fixture(scope="class")
def class_scope():
    print("Setup class scope")
    yield
    print("Teardown class scope")

@pytest.fixture(scope="module")
def module_scope():
    print("Setup module scope")
    yield
    print("Teardown module scope")

@pytest.fixture(scope="session")
def session_scope():
    print("Setup session scope")
    yield
    print("Teardown session scope")

class TestExample:
    def test_one(self, func_scope, class_scope, module_scope, session_scope):
        assert True

    def test_two(self, func_scope, class_scope, module_scope, session_scope):
        assert True

def test_three(func_scope, module_scope, session_scope):
    assert True

Execution Trace - 12 Steps

Step	Action	System State	Assertion	Result
1	pytest session starts and session_scope fixture setup runs once	Session scope fixture is set up, printed 'Setup session scope'	-	PASS
2	module_scope fixture setup runs once for the module	Module scope fixture is set up, printed 'Setup module scope'	-	PASS
3	class_scope fixture setup runs once before TestExample tests	Class scope fixture is set up, printed 'Setup class scope'	-	PASS
4	test_one starts, func_scope fixture setup runs	Function scope fixture is set up, printed 'Setup function scope'	assert True passes	PASS
5	test_one ends, func_scope fixture teardown runs	Function scope fixture is torn down, printed 'Teardown function scope'	-	PASS
6	test_two starts, func_scope fixture setup runs	Function scope fixture is set up again, printed 'Setup function scope'	assert True passes	PASS
7	test_two ends, func_scope fixture teardown runs	Function scope fixture is torn down, printed 'Teardown function scope'	-	PASS
8	class_scope fixture teardown runs after all TestExample tests	Class scope fixture is torn down, printed 'Teardown class scope'	-	PASS
9	test_three starts, func_scope fixture setup runs	Function scope fixture is set up, printed 'Setup function scope'	assert True passes	PASS
10	test_three ends, func_scope fixture teardown runs	Function scope fixture is torn down, printed 'Teardown function scope'	-	PASS
11	module_scope fixture teardown runs after all tests in module	Module scope fixture is torn down, printed 'Teardown module scope'	-	PASS
12	session_scope fixture teardown runs after all tests in session	Session scope fixture is torn down, printed 'Teardown session scope'	-	PASS

Failure Scenario

Failing Condition: Fixture setup or teardown fails or fixture is not found

Execution Trace Quiz - 3 Questions

Which fixture scope causes the setup to run once per test function?

A class

B function

C module

D session

Key Result

Use fixture scopes to control how often setup and teardown code runs, improving test efficiency and clarity.