Root cause analysis in Testing Fundamentals - Test Execution Trace

Test Overview

This test simulates a simple login functionality check and demonstrates how root cause analysis helps identify the exact reason for a test failure.

Test Code - Selenium

Testing Fundamentals

import unittest
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

class LoginTest(unittest.TestCase):
    def setUp(self):
        self.driver = webdriver.Chrome()
        self.driver.get('https://example.com/login')

    def test_login_with_valid_credentials(self):
        driver = self.driver
        # Wait for username field
        WebDriverWait(driver, 10).until(EC.presence_of_element_located((By.ID, 'username')))
        username_input = driver.find_element(By.ID, 'username')
        username_input.send_keys('validUser')

        # Wait for password field
        WebDriverWait(driver, 10).until(EC.presence_of_element_located((By.ID, 'password')))
        password_input = driver.find_element(By.ID, 'password')
        password_input.send_keys('validPass')

        # Click login button
        login_button = driver.find_element(By.ID, 'loginBtn')
        login_button.click()

        # Wait for welcome message
        welcome_message = WebDriverWait(driver, 10).until(
            EC.presence_of_element_located((By.ID, 'welcomeMsg'))
        )

        self.assertEqual(welcome_message.text, 'Welcome validUser!')

    def tearDown(self):
        self.driver.quit()

if __name__ == '__main__':
    unittest.main()

Execution Trace - 8 Steps

Step	Action	System State	Assertion	Result
1	Test starts and opens Chrome browser	Browser window opens at 'https://example.com/login' page	-	PASS
2	Waits for username input field to be present	Login page loaded with username input visible	Presence of element with ID 'username'	PASS
3	Finds username input and enters 'validUser'	Username field filled with 'validUser'	-	PASS
4	Waits for password input field to be present	Password input field visible on login page	Presence of element with ID 'password'	PASS
5	Finds password input and enters 'validPass'	Password field filled with 'validPass'	-	PASS
6	Finds and clicks the login button	Login button clicked, form submitted	-	PASS
7	Waits for welcome message element to appear	Page attempts to load welcome message with ID 'welcomeMsg'	Presence of element with ID 'welcomeMsg'	FAIL
8	Assertion to check welcome message text 'Welcome validUser!'	No welcome message found, test cannot verify text	welcome_message.text == 'Welcome validUser!'	FAIL

Failure Scenario

Failing Condition: The welcome message element with ID 'welcomeMsg' does not appear after login

Execution Trace Quiz - 3 Questions

At which step did the test first fail?

A Clicking the login button

B Entering the password

C Waiting for the welcome message element

D Opening the browser

Key Result

Root cause analysis helps pinpoint the exact step and reason for failure, enabling focused debugging and faster fixes.