Selenium for Python. Chapter 6. Page Objects

Continuation of the translation of the unofficial Selenium documentation for Python.
The original can be found here .

Content:

1. Installation
2. First steps
3. Navigation
4. Search for items
5. Expectations
6. Page Objects
7. WebDriver API
8. Appendix: Frequently Asked Questions

6. Page Objects

This section is an introduction to the guide to page object design patterns. The page object is the user interface area in the web application that your test will interact with.
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Advantages of using page object patterns:

• Create reusable code that can be used among many test cases.
• Reducing the amount of duplicate code
• If the user interface changes, it requires editing in just one place.

6.1 Test case

Below is a test case that searches for a word on python.org and shows that a certain result has been found.

import unittest from selenium import webdriver import page class PythonOrgSearch(unittest.TestCase): """A sample test class to show how page object works""" def setUp(self): self.driver = webdriver.Firefox() self.driver.get("http://www.python.org") def test_search_in_python_org(self): """ Tests python.org search feature. Searches for the word "pycon" then verified that some results show up. Note that it does not look for any particular text in search results page. This test verifies that the results were not empty. """ #Load the main page. In this case the home page of Python.og. main_page = page.MainPage(self.driver) #Checks if the word "Python" is in title assert main_page.is_title_matches(), "python.org title doesn't match." #Sets the text of search textbox to "pycon" main_page.search_text_element = "pycon" main_page.click_go_button() search_results_page = page.SearchResultsPage(self.driver) #Verifies that the results page is not empty assert search_results_page.is_results_found(), "No results found." def tearDown(self): self.driver.close() if __name__ == "__main__": unittest.main() 

6.2 Page Object Classes

The page object pattern intends to create an object for each web page. Following this technique, a separation layer is created between the test code and the technical implementation.

page.py will look something like this:

 from element import BasePageElement from locators import MainPageLocators class SearchTextElement(BasePageElement): """This class gets the search text from the specified locator""" #The locator for search box where search string is entered locator = 'q' class BasePage(object): """Base class to initialize the base page that will be called from all pages""" def __init__(self, driver): self.driver = driver class MainPage(BasePage): """Home page action methods come here. Ie Python.org""" #Declares a variable that will contain the retrieved text search_text_element = SearchTextElement() def is_title_matches(self): """Verifies that the hardcoded text "Python" appears in page title""" return "Python" in self.driver.title def click_go_button(self): """Triggers the search""" element = self.driver.find_element(*MainPageLocators.GO_BUTTON) element.click() class SearchResultsPage(BasePage): """Search results page action methods come here""" def is_results_found(self): # Probably should search for this text in the specific page # element, but as for now it works fine return "No results found." not in self.driver.page_source 

6.3 Page Elements

element.py will look like this:

 from selenium.webdriver.support.ui import WebDriverWait class BasePageElement(object): """Base page class that is initialized on every page object class.""" def __set__(self, obj, value): """Sets the text to the value supplied""" driver = obj.driver WebDriverWait(driver, 100).until( lambda driver: driver.find_element_by_name(self.locator)) driver.find_element_by_name(self.locator).send_keys(value) def __get__(self, obj, owner): """Gets the text of the specified object""" driver = obj.driver WebDriverWait(driver, 100).until( lambda driver: driver.find_element_by_name(self.locator)) element = driver.find_element_by_name(self.locator) return element.get_attribute("value") 

6.4 Locators

One method is to select the locator strings from the place where they will be used. In this example, locators on the same page belong to the same class.

locators.py will look like this:

 from selenium.webdriver.common.by import By class MainPageLocators(object): """A class for main page locators. All main page locators should come here""" GO_BUTTON = (By.ID, 'submit') class SearchResultsPageLocators(object): """A class for search results locators. All search results locators should come here""" pass