@pytest.mark.parametrize decorator - Test Execution Trace

Test Overview

This test uses @pytest.mark.parametrize to run the same test function with different input values. It verifies that the function correctly doubles the input number.

Test Code - pytest

PyTest

import pytest

@pytest.mark.parametrize("input_value,expected", [
    (1, 2),
    (5, 10),
    (0, 0),
    (-3, -6)
])
def test_double(input_value, expected):
    result = input_value * 2
    assert result == expected, f"Expected {expected} but got {result}"

Execution Trace - 4 Steps

Step	Action	System State	Assertion	Result
1	Test starts with parameter input_value=1 and expected=2	Test environment ready, no browser involved	Check if 1 * 2 equals 2	PASS
2	Test runs with parameter input_value=5 and expected=10	Test environment ready	Check if 5 * 2 equals 10	PASS
3	Test runs with parameter input_value=0 and expected=0	Test environment ready	Check if 0 * 2 equals 0	PASS
4	Test runs with parameter input_value=-3 and expected=-6	Test environment ready	Check if -3 * 2 equals -6	PASS

Failure Scenario

Failing Condition: The function returns a wrong doubled value for any input

Execution Trace Quiz - 3 Questions

What does the @pytest.mark.parametrize decorator do in this test?

A Skips the test function

B Runs the test function only once

C Runs the test function multiple times with different inputs

D Changes the test function name

Key Result

Using @pytest.mark.parametrize helps test the same logic with many inputs easily, improving test coverage and saving time.