Multiple parameters in PyTest - Test Execution Trace

Test Overview

This test checks a function that adds two numbers. It uses multiple parameters to test different pairs of numbers and verifies the sum is correct.

Test Code - pytest

PyTest

import pytest

@pytest.mark.parametrize("a,b,expected", [
    (1, 2, 3),
    (5, 5, 10),
    (10, -2, 8),
    (0, 0, 0)
])
def test_addition(a, b, expected):
    result = a + b
    assert result == expected, f"Expected {expected} but got {result}"

Execution Trace - 7 Steps

Step	Action	System State	Assertion	Result
1	Test starts	pytest test runner initialized	-	PASS
2	Test runner reads @pytest.mark.parametrize with parameters (a,b,expected)	Test cases prepared for each parameter set	-	PASS
3	Test case 1 runs with a=1, b=2, expected=3	Function adds 1 + 2	Check if result == 3	PASS
4	Test case 2 runs with a=5, b=5, expected=10	Function adds 5 + 5	Check if result == 10	PASS
5	Test case 3 runs with a=10, b=-2, expected=8	Function adds 10 + (-2)	Check if result == 8	PASS
6	Test case 4 runs with a=0, b=0, expected=0	Function adds 0 + 0	Check if result == 0	PASS
7	All parameterized tests complete	Test report generated with all passes	-	PASS

Failure Scenario

Failing Condition: If the function returns a wrong sum for any parameter set

Execution Trace Quiz - 3 Questions

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

A Runs the test multiple times with different input values

B Skips the test

C Runs the test only once

D Changes the test function name

Key Result

Using multiple parameters in tests helps check many input cases easily and ensures the function works correctly for different values.