Base page class in Selenium Python

Introduction

A base page class helps keep your test code clean and organized by putting common web page actions in one place.

When you test many web pages that share similar actions like clicking or typing.

When you want to avoid repeating the same code in multiple test files.

When you want to make your tests easier to update if the website changes.

When you want to keep your test code simple and easy to read.

When you want to add common waits or checks for all pages in one place.

Syntax

Selenium Python

class BasePage:
    def __init__(self, driver):
        self.driver = driver

    def find_element(self, locator):
        return self.driver.find_element(*locator)

    def click(self, locator):
        element = self.find_element(locator)
        element.click()

    def type_text(self, locator, text):
        element = self.find_element(locator)
        element.clear()
        element.send_keys(text)

The driver is the browser control object from Selenium.

Locators are usually tuples like (By.ID, 'element_id').

Examples

This example shows how to store the driver and find an element using a locator tuple.

Selenium Python

from selenium.webdriver.common.by import By

class BasePage:
    def __init__(self, driver):
        self.driver = driver

    def find_element(self, locator):
        return self.driver.find_element(*locator)

This method clicks on the element found by the locator.

Selenium Python

def click(self, locator):
    element = self.find_element(locator)
    element.click()

This method clears any existing text and types new text into an input field.

Selenium Python

def type_text(self, locator, text):
    element = self.find_element(locator)
    element.clear()
    element.send_keys(text)

Sample Program

This script opens a browser, navigates to example.com, and tries to type and click using the base page methods. It prints if the test passed or failed.

Selenium Python

from selenium import webdriver
from selenium.webdriver.common.by import By
import time

class BasePage:
    def __init__(self, driver):
        self.driver = driver

    def find_element(self, locator):
        return self.driver.find_element(*locator)

    def click(self, locator):
        element = self.find_element(locator)
        element.click()

    def type_text(self, locator, text):
        element = self.find_element(locator)
        element.clear()
        element.send_keys(text)

# Example usage:
if __name__ == '__main__':
    driver = webdriver.Chrome()
    driver.get('https://www.example.com')

    base_page = BasePage(driver)

    # Example locators (these won't work on example.com, just for demo)
    search_box = (By.NAME, 'q')
    search_button = (By.NAME, 'btnK')

    try:
        base_page.type_text(search_box, 'Selenium')
        base_page.click(search_button)
        print('Test passed: Typed text and clicked button')
    except Exception as e:
        print(f'Test failed: {e}')
    finally:
        time.sleep(2)
        driver.quit()

Important Notes

Always pass the Selenium driver to the base page class when creating it.

Use locator tuples like (By.ID, 'id_value') for better readability and maintainability.

Handle exceptions in your tests to know if an element was not found or an action failed.

Summary

A base page class groups common web page actions to avoid repeating code.

It makes tests easier to write, read, and update.

Use locator tuples and pass the driver to the base page class.

Practice

1. What is the main purpose of a BasePage class in Selenium Python testing?

easy

A. To group common web page actions and locators for reuse

B. To store test data for different test cases

C. To define the browser settings and capabilities

D. To generate test reports automatically

Solution

1. Step 1: Understand the role of BasePage

   The BasePage class is designed to hold common actions and locators shared by multiple page classes.

2. Step 2: Compare with other options

   Storing test data, browser settings, or generating reports are not responsibilities of BasePage.

3. Final Answer:

   To group common web page actions and locators for reuse -> Option A

4. Quick Check:

   BasePage groups common actions [OK]

Hint: BasePage holds shared page methods and locators [OK]

Common Mistakes:

• Confusing BasePage with test data storage
• Thinking BasePage manages browser setup
• Assuming BasePage creates reports

2. Which of the following is the correct way to define a locator tuple in a BasePage class?

easy

A. submit_button = (By.ID, 'submit')

B. submit_button = ['id', 'submit']

C. submit_button = {'id': 'submit'}

D. submit_button = By.ID('submit')

Solution

1. Step 1: Recall locator tuple syntax

   Locator tuples use the format (By.<METHOD>, 'value'), e.g., (By.ID, 'submit').

2. Step 2: Check each option

   submit_button = (By.ID, 'submit') matches the tuple format. The other options use wrong data structures or invalid syntax.

3. Final Answer:

   submit_button = (By.ID, 'submit') -> Option A

4. Quick Check:

   Locator tuple = (By.METHOD, 'value') [OK]

Hint: Locator tuples always use parentheses and By constants [OK]

Common Mistakes:

• Using lists or dicts instead of tuples for locators
• Calling By.ID as a function
• Missing parentheses around locator tuple

3. Given this BasePage method, what will page.get_title() return if the browser's current page title is "Welcome Page"?

class BasePage:
    def __init__(self, driver):
        self.driver = driver

    def get_title(self):
        return self.driver.title

page = BasePage(driver)

medium

A. An error because get_title has no return

B. self.driver

C. None

D. "Welcome Page"

Solution

1. Step 1: Understand get_title method

   The method returns self.driver.title, which is the current page title string.

2. Step 2: Check given title

   The browser's current page title is "Welcome Page", so the method returns that string.

3. Final Answer:

   "Welcome Page" -> Option D

4. Quick Check:

   get_title returns driver.title = "Welcome Page" [OK]

Hint: get_title returns driver.title string [OK]

Common Mistakes:

• Thinking it returns the driver object
• Assuming no return means None
• Confusing method with attribute

4. Identify the error in this BasePage method and how to fix it:

class BasePage:
    def __init__(self, driver):
        self.driver = driver

    def click_element(locator):
        element = self.driver.find_element(*locator)
        element.click()

medium

A. Using find_element instead of find_elements

B. Missing 'self' parameter in click_element method

C. Locator should be a string, not a tuple

D. element.click() should be element.click

Solution

1. Step 1: Check method parameters

   Instance methods must have 'self' as the first parameter. Here, click_element lacks 'self'.

2. Step 2: Understand impact

   Without 'self', calling click_element will cause a TypeError because 'self.driver' is undefined.

3. Final Answer:

   Missing 'self' parameter in click_element method -> Option B

4. Quick Check:

   Instance methods need 'self' first [OK]

Hint: Always include 'self' as first method parameter [OK]

Common Mistakes:

• Forgetting 'self' in instance methods
• Confusing find_element with find_elements
• Misunderstanding locator types
• Using method call without parentheses

5. You want to create a BasePage method is_element_visible that returns True if an element is visible and False if not, without raising exceptions. Which is the best way to implement it?

hard

A. Use driver.page_source to search for element HTML string

B. Call find_element and return True without exception handling

C. Use try-except to catch NoSuchElementException and return False if caught

D. Use find_elements and check if list length is greater than zero

Solution

1. Step 1: Understand element visibility check

   Using find_element raises NoSuchElementException if element not found, so we must handle it.

2. Step 2: Use try-except for safe check

   Try to find element and check is_displayed(). If exception occurs, return False safely.

3. Final Answer:

   Use try-except to catch NoSuchElementException and return False if caught -> Option C

4. Quick Check:

   Try-except handles missing element safely [OK]

Hint: Wrap find_element in try-except to avoid exceptions [OK]

Common Mistakes:

• Not handling exceptions causing test failure
• Assuming find_elements always returns visible elements
• Searching page_source is unreliable and slow