Parametrize with indirect fixtures in PyTest - Test Execution Trace

Test Overview

This test uses pytest to run the same test function multiple times with different inputs. It uses an indirect fixture to prepare the input before the test runs. The test checks if the input string is converted to uppercase correctly.

Test Code - pytest

PyTest

import pytest

@pytest.fixture
def input_data(request):
    # Prepare the input by converting to uppercase
    return request.param.upper()

@pytest.mark.parametrize('input_data', ['hello', 'world'], indirect=True)
def test_uppercase(input_data):
    assert input_data.isupper(), f"Expected uppercase but got {input_data}"

Execution Trace - 7 Steps

Step	Action	System State	Assertion	Result
1	Test starts	pytest test runner initialized	-	PASS
2	pytest collects test_uppercase with parametrize inputs ['hello', 'world'] and indirect=True	Test function identified with two parameter sets	-	PASS
3	For first parameter 'hello', pytest calls fixture input_data(request) with request.param='hello'	Fixture input_data prepares 'HELLO'	-	PASS
4	test_uppercase runs with input_data='HELLO'	Test function receives 'HELLO'	Check if 'HELLO'.isupper() is True	PASS
5	For second parameter 'world', pytest calls fixture input_data(request) with request.param='world'	Fixture input_data prepares 'WORLD'	-	PASS
6	test_uppercase runs with input_data='WORLD'	Test function receives 'WORLD'	Check if 'WORLD'.isupper() is True	PASS
7	Test ends with all parameter sets passed	Test report shows 2 passed tests	-	PASS

Failure Scenario

Failing Condition: Fixture input_data does not convert string to uppercase correctly

Execution Trace Quiz - 3 Questions

What does the 'indirect=True' parameter do in pytest.mark.parametrize?

A It skips the test for that parameter

B It runs the test only once ignoring parameters

C It tells pytest to pass the parameter value to a fixture instead of directly to the test function

D It marks the test as expected to fail

Key Result

Using indirect fixtures with parametrize allows you to preprocess or prepare test inputs dynamically before the test runs, making tests more flexible and reusable.