Test case writing in Testing Fundamentals - Test Execution Trace

Test Overview

This test case checks if the login form accepts valid user credentials and successfully logs the user in by verifying the presence of a welcome message.

Test Code - Selenium with Python unittest

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_valid_login(self):
        driver = self.driver
        # Find username field and enter username
        username_field = WebDriverWait(driver, 10).until(
            EC.presence_of_element_located((By.ID, 'username'))
        )
        username_field.send_keys('validUser')

        # Find password field and enter password
        password_field = driver.find_element(By.ID, 'password')
        password_field.send_keys('validPass123')

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

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

        # Assert welcome message text
        self.assertEqual(welcome_message.text, 'Welcome, validUser!')

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

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

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test starts and Chrome browser opens	Browser is open at 'https://example.com/login' page showing login form with username, password fields and login button	-	PASS
2	Find username input field by ID 'username' and enter 'validUser'	Username field is filled with 'validUser'	-	PASS
3	Find password input field by ID 'password' and enter 'validPass123'	Password field is filled with 'validPass123'	-	PASS
4	Find login button by ID 'loginBtn' and click it	Login button clicked, page starts processing login	-	PASS
5	Wait for welcome message element with ID 'welcomeMsg' to appear	Welcome message element is visible on page	Check that welcome message text equals 'Welcome, validUser!'	PASS
6	Test ends and browser closes	Browser window closed	-	PASS

Failure Scenario

Failing Condition: Welcome message element does not appear or text does not match expected after login

Execution Trace Quiz - 3 Questions

What does the test verify after clicking the login button?

A That the login button disappears

B That the welcome message with correct text appears

C That the username field is cleared

D That the password field becomes visible

Key Result

Always write test cases that clearly describe the steps and expected results, including waiting for elements to appear before asserting, to avoid flaky tests.