Selenium - WebDriver: Page Objects

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This chapter is a tutorial introduction to page objects design pattern. A page object represents an area in the web application user interface that your test is interacting.

Benefits of using page object pattern:

• Creating reusable code that can be shared across multiple test cases
• Reducing the amount of duplicated code
• If the user interface changes, the fix needs changes in only one place

1. Test case

Here is a test case which searches for a word in python.org website and ensure some results are found.

import unittestfrom selenium import webdriverimport pageclass 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.org.        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()

2. Page object classes

The page object pattern intends creating an object for each web page. By following this technique a layer of separation between the test code and technical implementation is created.

The page.py will look like this:

from element import BasePageElementfrom locators import MainPageLocatorsclass 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 = driverclass MainPage(BasePage):    """Home page action methods come here. I.e. 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

3. Page elements

The element.py will look like this:

from selenium.webdriver.support.ui import WebDriverWaitclass 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")

4. Locators

One of the practices is to separate the locator strings from the place where they are being used. In this example, locators of the same page belong to same class.

The locators.py will look like this:

from selenium.webdriver.common.by import Byclass 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

 

Selenium - WebDriver: Page Objects