Test functions in PyTest - Test Execution Trace

Test Overview

This test checks if the function add_numbers correctly adds two numbers and returns the expected result.

Test Code - PyTest

PyTest

import pytest

def add_numbers(a, b):
    return a + b

def test_add_numbers():
    result = add_numbers(3, 4)
    assert result == 7, f"Expected 7 but got {result}"

Execution Trace - 5 Steps

Step	Action	System State	Assertion	Result
1	Test starts	PyTest test runner initialized	-	PASS
2	PyTest discovers test function 'test_add_numbers'	Test function ready to run	-	PASS
3	Calls function add_numbers(3, 4)	Function executes and returns 7	-	PASS
4	Assert that result == 7	Result is 7	Check if 7 equals 7	PASS
5	Test completes successfully	Test passed with no errors	-	PASS

Failure Scenario

Failing Condition: The add_numbers function returns a wrong sum, e.g., 8 instead of 7

Execution Trace Quiz - 3 Questions

What does the test function 'test_add_numbers' verify?

A That add_numbers(3, 4) returns 7

B That add_numbers(3, 4) returns 8

C That add_numbers raises an error

D That add_numbers returns a string

Key Result

Always write simple test functions that clearly check one behavior using assert statements for easy debugging.