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.

Practice

1. What is the main purpose of writing test cases in software testing?

easy

A. To write the program code

B. To describe step-by-step how to test a feature

C. To design the user interface

D. To create marketing materials

Solution

1. Step 1: Understand the role of test cases

   Test cases provide clear instructions on how to test a specific feature or function.

2. Step 2: Differentiate from other activities

   Writing code, designing UI, or marketing are not related to test case writing.

3. Final Answer:

   To describe step-by-step how to test a feature -> Option B

4. Quick Check:

   Test case purpose = step-by-step test guide [OK]

Hint: Test cases guide testing steps clearly [OK]

Common Mistakes:

• Confusing test cases with coding tasks
• Thinking test cases design UI
• Mixing test cases with marketing

2. Which of the following is the correct format for a test case title?

easy

A. Test login with valid username and password

B. Check if login works

C. LoginTest123

D. TestCase1

Solution

1. Step 1: Identify clear and descriptive titles

   A good test case title clearly describes what is being tested, like Test login with valid username and password.

2. Step 2: Evaluate other options

   Options A, B, and C are vague or not descriptive enough for easy understanding.

3. Final Answer:

   Test login with valid username and password -> Option A

4. Quick Check:

   Clear descriptive title = Test login with valid username and password [OK]

Hint: Use clear, descriptive titles for test cases [OK]

Common Mistakes:

• Using vague or generic titles
• Using codes or numbers only
• Not describing the test purpose

3. Given this test case step: Enter username 'user1' and password 'pass123', what is the expected result?

medium

A. Page reloads without change

B. Error message appears

C. User is logged in successfully

D. Username and password fields clear

Solution

1. Step 1: Understand the test step

   The step inputs valid credentials, so the expected result is successful login.

2. Step 2: Analyze other options

   Error message or no change would mean failure, which is not expected here.

3. Final Answer:

   User is logged in successfully -> Option C

4. Quick Check:

   Valid login inputs = successful login [OK]

Hint: Valid inputs usually lead to success expected result [OK]

Common Mistakes:

• Assuming error message for valid inputs
• Confusing page reload with success
• Ignoring expected behavior for valid data

4. Identify the error in this test case step: Click the 'Submit' button without entering any data with expected result: Form submits successfully.

medium

A. Expected result should be an error message, not success

B. Step should include entering data before submit

C. Button name is incorrect

D. No error, test case is correct

Solution

1. Step 1: Analyze the test step

   Clicking submit without data usually triggers validation errors, not success.

2. Step 2: Check expected result correctness

   Expected result should be an error message indicating missing data.

3. Final Answer:

   Expected result should be an error message, not success -> Option A

4. Quick Check:

   Empty submit triggers error, not success [OK]

Hint: Empty form submit expects error, not success [OK]

Common Mistakes:

• Expecting success without input
• Ignoring validation rules
• Assuming button name error

5. You need to write a test case for a password reset feature that requires entering an email and clicking 'Reset'. Which of these is the best test case title and expected result pair?

hard

A. Reset password; Expected: Password changes immediately

B. Check password reset button; Expected: Button is clickable

C. Password reset test; Expected: Page reloads

D. Test password reset with valid email; Expected: Reset link sent to email

Solution

1. Step 1: Evaluate clarity of test case title

   Test password reset with valid email; Expected: Reset link sent to email clearly states the action and input (valid email) for password reset.

2. Step 2: Check expected result relevance

   Test password reset with valid email; Expected: Reset link sent to email's expected result matches the feature behavior: sending reset link.

3. Final Answer:

   Test password reset with valid email; Expected: Reset link sent to email -> Option D

4. Quick Check:

   Clear title + correct expected result = Test password reset with valid email; Expected: Reset link sent to email [OK]

Hint: Match test title and expected result clearly [OK]

Common Mistakes:

• Using vague titles
• Wrong expected results
• Ignoring feature behavior