Page Object Model concept in Testing Fundamentals - Build an Automation Script

Automate login functionality using Page Object Model

Preconditions (2)

Step 1: Open the login page URL

Step 2: Enter '[e-mail]' in the email input field

Step 3: Enter 'Password123' in the password input field

Step 4: Click the login button

Step 5: Verify that the user is redirected to the dashboard page

Step 6: Verify that the dashboard page contains a welcome message

✅ Expected Result: User successfully logs in and sees the dashboard page with a welcome message

Automation Requirements - Selenium with Python

Assertions Needed:

Verify current URL is dashboard URL after login

Verify presence of welcome message element on dashboard

Best Practices:

Use Page Object Model to separate page locators and actions

Use explicit waits to wait for elements before interacting

Keep test logic separate from page object classes

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

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, 'loginBtn')

    def open(self, url):
        self.driver.get(url)

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

    def enter_password(self, password):
        WebDriverWait(self.driver, 10).until(
            EC.visibility_of_element_located(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, 'welcomeMsg')

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


def test_login():
    driver = webdriver.Chrome()
    login_page = LoginPage(driver)
    dashboard_page = DashboardPage(driver)

    try:
        login_page.open('https://example.com/login')
        login_page.enter_email('[e-mail]')
        login_page.enter_password('Password123')
        login_page.click_login()

        WebDriverWait(driver, 10).until(
            EC.url_contains('/dashboard')
        )

        assert '/dashboard' in driver.current_url, 'URL after login is incorrect'
        assert dashboard_page.is_welcome_message_displayed(), 'Welcome message not found on dashboard'

    finally:
        driver.quit()

if __name__ == '__main__':
    test_login()

This code uses the Page Object Model to organize the test.

The LoginPage class holds locators and actions for the login page. It has methods to open the page, enter email, enter password, and click login. Each method waits explicitly for the element to be ready before interacting.

The DashboardPage class holds the locator and method to check if the welcome message is visible on the dashboard.

The test_login function creates a browser driver, uses the page objects to perform the login steps, waits for the dashboard URL, and asserts the URL and welcome message presence.

Explicit waits ensure the test does not fail due to slow loading. Separating page details from test logic makes the code easier to maintain and read.

Common Mistakes - 3 Pitfalls

Putting locators and test steps directly in the test function

Using fixed sleep delays instead of explicit waits

Not verifying the page URL after login

Bonus Challenge

Now add data-driven testing with 3 different sets of login credentials (valid and invalid).

Show Hint

Practice

1. What is the main purpose of the Page Object Model in software testing?

easy

A. To combine multiple test cases into one large script

B. To write all test steps inside the test script without abstraction

C. To separate page structure from test logic for easier maintenance

D. To avoid using classes and methods in test automation

Solution

1. Step 1: Understand the role of Page Object Model

   The Page Object Model (POM) is designed to separate the page details like locators and actions from the test scripts.

2. Step 2: Identify the benefit of separation

   This separation makes tests easier to read, write, and maintain because changes in the UI only affect the page objects, not the test logic.

3. Final Answer:

   To separate page structure from test logic for easier maintenance -> Option C

4. Quick Check:

   Separation of concerns = A [OK]

Hint: POM separates page details from tests for easy updates [OK]

Common Mistakes:

• Thinking POM combines all tests into one script
• Believing POM avoids using classes and methods
• Confusing POM with writing test steps directly in scripts

2. Which of the following is the correct way to define a page object class for a login page in Python?

easy

A. class LoginPage:
def __init__(self, driver):
self.driver = driver

B. def LoginPage(driver):
self.driver = driver

C. class LoginPage:
driver = driver

D. LoginPage = function(driver) { this.driver = driver; }

Solution

1. Step 1: Check Python class syntax for page object

   In Python, a page object is a class with an __init__ method that accepts the driver and assigns it to self.driver.

2. Step 2: Identify correct syntax

   class LoginPage: def __init__(self, driver): self.driver = driver correctly defines a class with __init__ and assigns driver properly. Options A, B, and D have syntax errors or misuse of class variables. LoginPage = function(driver) { this.driver = driver; } is JavaScript syntax, not Python.

3. Final Answer:

   class LoginPage: def __init__(self, driver): self.driver = driver -> Option A

4. Quick Check:

   Python class with __init__ = C [OK]

Hint: Python page objects use class with __init__ for driver [OK]

Common Mistakes:

• Using function instead of class for page object
• Assigning driver outside __init__ method
• Mixing JavaScript syntax in Python code

3. Given this Python page object method, what will login_page.get_title() return if the page title is "Welcome"?

class LoginPage:
    def __init__(self, driver):
        self.driver = driver
    def get_title(self):
        return self.driver.title

medium

A. "Welcome"

B. self.driver

C. None

D. Error: method missing return

Solution

1. Step 1: Understand the get_title method

   The method returns self.driver.title, which is the page title property from the driver object.

2. Step 2: Determine the returned value

   If the page title is "Welcome", calling get_title() returns the string "Welcome".

3. Final Answer:

   "Welcome" -> Option A

4. Quick Check:

   Method returns driver.title = "Welcome" [OK]

Hint: Method returns driver.title property value [OK]

Common Mistakes:

• Confusing method return with driver object itself
• Assuming method returns None without explicit return
• Thinking method causes error due to missing return

4. Identify the error in this page object method and select the fix:

class LoginPage:
    def __init__(self, driver):
        self.driver = driver
    def click_login(self):
        self.driver.find_element_by_id('loginBtn').click()

medium

A. Change method name to clickLogin

B. Use correct locator method: replace find_element_by_id with find_element(By.ID, 'loginBtn')

C. Remove self.driver assignment in __init__

D. Add return statement after click()

Solution

1. Step 1: Check Selenium locator method usage

   In recent Selenium versions, find_element_by_id is deprecated. The correct usage is find_element(By.ID, 'loginBtn') with proper import.

2. Step 2: Identify the fix

   Use correct locator method: replace find_element_by_id with find_element(By.ID, 'loginBtn') correctly updates the locator method. Other options do not fix the locator error or are unrelated.

3. Final Answer:

   Use correct locator method: replace find_element_by_id with find_element(By.ID, 'loginBtn') -> Option B

4. Quick Check:

   Update deprecated locator method = D [OK]

Hint: Use updated Selenium locators with By.ID [OK]

Common Mistakes:

• Ignoring deprecated locator methods
• Adding unnecessary return statements
• Changing method names without reason

5. You want to create a page object for a search page that has a method to enter text and submit the search. Which design best follows the Page Object Model principles?

hard

A. class SearchPage:
def __init__(self):
self.driver = None
def search(self, text):
self.driver.find_element(By.ID, 'searchBox').send_keys(text)

B. class SearchPage:
def search(self, text):
input = driver.find_element(By.NAME, 'q')
input.send_keys(text)
input.submit()

C. def search(text):
driver.find_element(By.NAME, 'q').send_keys(text)
driver.find_element(By.NAME, 'q').submit()

D. class SearchPage:
def __init__(self, driver):
self.driver = driver
def search(self, text):
box = self.driver.find_element(By.NAME, 'q')
box.clear()
box.send_keys(text)
box.submit()

Solution

1. Step 1: Check for proper driver initialization

   class SearchPage: def __init__(self, driver): self.driver = driver def search(self, text): box = self.driver.find_element(By.NAME, 'q') box.clear() box.send_keys(text) box.submit() correctly initializes the driver in __init__, so the page object has access to it.

2. Step 2: Verify method encapsulates actions

   The search method finds the input box, clears it, sends keys, and submits, all encapsulated in one method, following POM principles.

3. Final Answer:

   class SearchPage: def __init__(self, driver): self.driver = driver def search(self, text): box = self.driver.find_element(By.NAME, 'q') box.clear() box.send_keys(text) box.submit() -> Option D

4. Quick Check:

   Driver init + encapsulated method = A [OK]

Hint: Initialize driver in __init__ and encapsulate actions in methods [OK]

Common Mistakes:

• Not initializing driver in constructor
• Using global driver without passing it
• Splitting one action into multiple unrelated methods