Verify login button functionality using reliable selectors

Preconditions (1)

Step 1: Locate the email input field using a reliable selector and enter 'user@example.com'

Step 2: Locate the password input field using a reliable selector and enter 'Password123!'

Step 3: Locate the login button using a reliable selector and click it

Step 4: Wait for the dashboard page to load

Step 5: Verify that the URL is 'https://example.com/dashboard'

Step 6: Verify that a welcome message with id 'welcome-msg' is displayed

✅ Expected Result: User is successfully logged in and redirected to the dashboard page with a visible welcome message

Automation Requirements - Selenium with Python

Assertions Needed:

Verify current URL is 'https://example.com/dashboard'

Verify welcome message element is displayed

Best Practices:

Use By.ID or By.NAME selectors instead of brittle XPath or CSS selectors

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

Avoid hardcoded absolute XPath expressions

Use Page Object Model pattern for maintainability

Automated Solution

Selenium Python

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 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 login(self, email, password):
        WebDriverWait(self.driver, 10).until(EC.visibility_of_element_located(self.email_input)).send_keys(email)
        self.driver.find_element(*self.password_input).send_keys(password)
        self.driver.find_element(*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_displayed()


def test_login():
    driver = webdriver.Chrome()
    driver.get('https://example.com/login')

    login_page = LoginPage(driver)
    login_page.login('user@example.com', 'Password123!')

    WebDriverWait(driver, 10).until(EC.url_to_be('https://example.com/dashboard'))

    dashboard_page = DashboardPage(driver)
    assert dashboard_page.is_welcome_message_displayed(), 'Welcome message should be visible'

    driver.quit()

if __name__ == '__main__':
    test_login()

This script uses Selenium with Python to automate the login process.

We define Page Object Model classes for the login and dashboard pages. This keeps selectors and actions organized.

Selectors use By.ID which is reliable and less likely to break if the page layout changes.

We use explicit waits to wait for elements to be visible or for the URL to change. This avoids timing issues.

The test asserts that after login, the URL is correct and the welcome message is visible, confirming successful login.

This approach ensures the test is stable and easy to maintain, demonstrating why mastering selectors is key for reliability.

Common Mistakes - 3 Pitfalls

{'mistake': "Using absolute XPath selectors like '/html/body/div[2]/form/input[1]'", 'why_bad': 'These selectors break easily if the page structure changes even slightly.', 'correct_approach': "Use stable selectors like IDs or names, e.g., By.ID('email')"}

Not using explicit waits and using time.sleep() instead

Mixing different selector strategies inconsistently

Bonus Challenge

Now add data-driven testing with 3 different sets of login credentials to verify login success or failure.

Show Hint