Why test design drives efficiency in Testing Fundamentals - Test Execution Impact

Test Overview

This test checks how well a simple login form works by using a well-planned test design. It verifies that the login succeeds with correct data and fails with wrong data, showing how good test design saves time and effort.

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

    def test_login(self):
        driver = self.driver
        # Test data from designed test cases
        test_cases = [
            {'username': 'user1', 'password': 'pass1', 'should_pass': True},
            {'username': 'user1', 'password': 'wrongpass', 'should_pass': False}
        ]
        for case in test_cases:
            username_input = WebDriverWait(driver, 10).until(
                EC.presence_of_element_located((By.ID, 'username'))
            )
            password_input = driver.find_element(By.ID, 'password')
            login_button = driver.find_element(By.ID, 'login-btn')

            username_input.clear()
            username_input.send_keys(case['username'])
            password_input.clear()
            password_input.send_keys(case['password'])
            login_button.click()

            if case['should_pass']:
                welcome_msg = WebDriverWait(driver, 10).until(
                    EC.presence_of_element_located((By.ID, 'welcome-msg'))
                )
                self.assertIn('Welcome', welcome_msg.text)
            else:
                error_msg = WebDriverWait(driver, 10).until(
                    EC.presence_of_element_located((By.ID, 'error-msg'))
                )
                self.assertIn('Invalid', error_msg.text)

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

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

Execution Trace - 7 Steps

Step	Action	System State	Assertion	Result
1	Test starts and opens Chrome browser	Browser opens at https://example.com/login showing login form with username, password fields and login button	-	PASS
2	Find username, password input fields and login button	Login form elements are present and interactable	Check presence of username input field	PASS
3	Enter username 'user1' and password 'pass1', then click login	Login form filled with valid credentials and login button clicked	-	PASS
4	Wait for welcome message to appear	Page shows welcome message with text containing 'Welcome'	Verify welcome message text contains 'Welcome'	PASS
5	Clear inputs, enter username 'user1' and wrong password 'wrongpass', then click login	Login form filled with invalid credentials and login button clicked	-	PASS
6	Wait for error message to appear	Page shows error message with text containing 'Invalid'	Verify error message text contains 'Invalid'	PASS
7	Close browser and end test	Browser closed	-	PASS

Failure Scenario

Failing Condition: If the login page elements are missing or the messages do not appear as expected

Execution Trace Quiz - 3 Questions

What does the test verify after entering correct login details?

A That the login button is disabled

B That an error message appears containing 'Invalid'

C That a welcome message appears containing 'Welcome'

D That the page URL changes to /error

Key Result

Good test design selects key input cases to cover important behaviors, reducing test time and improving clarity.