Verify login functionality based on user story

Preconditions (2)

Step 1: Enter 'user@example.com' in the email input field

Step 2: Enter 'Password123!' in the password input field

Step 3: Click the 'Login' button

Step 4: Wait for the dashboard page to load

✅ Expected Result: User is successfully logged in and redirected to the dashboard page with URL containing '/dashboard'

Automation Requirements - Selenium with Python

Assertions Needed:

Verify current URL contains '/dashboard'

Verify presence of a welcome message element on the dashboard page

Best Practices:

Use explicit waits to wait for elements to be visible or clickable

Use Page Object Model to separate page locators and actions

Use clear and descriptive assertion messages

Automated Solution

Testing Fundamentals

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
import unittest

class LoginPage:
    def __init__(self, driver):
        self.driver = driver
        self.email_input = (By.ID, 'email')
        self.password_input = (By.ID, 'password')
        self.login_button = (By.ID, 'login-btn')

    def enter_email(self, email):
        WebDriverWait(self.driver, 10).until(EC.visibility_of_element_located(self.email_input)).clear()
        self.driver.find_element(*self.email_input).send_keys(email)

    def enter_password(self, password):
        WebDriverWait(self.driver, 10).until(EC.visibility_of_element_located(self.password_input)).clear()
        self.driver.find_element(*self.password_input).send_keys(password)

    def click_login(self):
        WebDriverWait(self.driver, 10).until(EC.element_to_be_clickable(self.login_button)).click()

class DashboardPage:
    def __init__(self, driver):
        self.driver = driver
        self.welcome_message = (By.ID, 'welcome-msg')

    def is_welcome_message_displayed(self):
        return WebDriverWait(self.driver, 10).until(EC.visibility_of_element_located(self.welcome_message)) is not None

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

    def test_valid_login(self):
        login_page = LoginPage(self.driver)
        login_page.enter_email('user@example.com')
        login_page.enter_password('Password123!')
        login_page.click_login()

        # Wait for URL to contain '/dashboard'
        WebDriverWait(self.driver, 10).until(EC.url_contains('/dashboard'))

        self.assertIn('/dashboard', self.driver.current_url, 'URL does not contain /dashboard after login')

        dashboard_page = DashboardPage(self.driver)
        self.assertTrue(dashboard_page.is_welcome_message_displayed(), 'Welcome message not displayed on dashboard')

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

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

This test script uses Selenium with Python and unittest framework to automate the user story test case.

We define two page classes: LoginPage and DashboardPage to keep locators and actions organized (Page Object Model).

In test_valid_login, we enter the email and password, click login, then wait explicitly for the URL to contain '/dashboard'.

We assert the URL contains '/dashboard' and that the welcome message is visible on the dashboard page.

Explicit waits ensure the test waits for elements or URL changes properly, avoiding flaky tests.

The setUp and tearDown methods handle browser start and close for clean test runs.

Common Mistakes - 3 Pitfalls

{'mistake': 'Using time.sleep() instead of explicit waits', 'why_bad': 'It causes tests to wait longer than needed or fail if the page loads slower or faster than expected.', 'correct_approach': "Use Selenium's explicit waits like WebDriverWait with expected_conditions to wait for specific elements or URL changes."}

Hardcoding XPath locators that are brittle

Mixing locators and test logic in the test method

Bonus Challenge

Now add data-driven testing with 3 different sets of login credentials: one valid, two invalid

Show Hint