Web UI automation using Selenium

Automate web UI testing with Python and Selenium

Pycon India 2018

 

Abhiram Ravikumar

@abhi12ravi

5th Oct 2018

Bhoomika Agarwal

@myriadbhoom

Bhoomika Agarwal

  • LinkedIn Learning Instructor
  • Data Science Enthusiast
  • Poet 
  • Developer at SAP Labs

Abhiram Ravikumar

  • Mozilla Tech Speaker
  • Open Source evangelist
  • Data Science Enthusiast
  • LinkedIn Learning Instructor
  • Developer at SAP Labs

Facilitators

Contents

 

  • Why do we need to automate testing
  • Automated testing
  • Python Selenium bindings
  • Locating elements on a page
  • Navigating through pages
  • Waits
  • Best practices
  • Recap

Why do we need to automate testing?

  • Decreased cost and time of testing
  • Enable continuous delivery through round-the-clock testing
  • Ensure regression testing
  • Increased test coverage
  • Cross-device testing made easy

 

Automated Testing

Mike Cohn's test automation pyramid

Good read

Cost

Quality
Time

So, where does Python fit in?

unittest

Selenium bindings for Python

  • Web UI Automation means the automatic execution of the actions performed in a web browser window
  • Selenium automates browsers
  • Selenium WebDriver is the one that can automate all these tasks.

  • Used to scale tests to multiple browsers and environments using the selenium grid

+

Selenium bindings for Python

  • Installing Selenium
  • Simple test script
#Python selenium bindings installation
pip install selenium 

#Test script
from selenium import webdriver
import time
driver= webdriver.Firefox()
driver.get('http://seleniumhq.org')
time.sleep(2)
driver.close()

Locating elements

  • Uses the id tag to locate elements in a page

  • The HTML ‘id’ attribute specifies a unique id for a HTML element

  • The rules for the ‘id’ attribute are-

    1. At least one character

    2. No space characters

    3. Case sensitive

    4. Unique

#Find element by ID
login_form = driver.find_element_by_id('loginForm')

Locating by id

Locating elements

  • Uses the name tag to locate elements in a page
  • Multiple elements might share a name

  • Usually used in forms to reference the element when data is submitted. 

# Find username and password by name
username = driver.find_element_by_name('username')
password = driver.find_element_by_name('password')

#Returns login
continue = driver.find_element_by_name('continue')

Locating by name

Locating elements

  • Used when you don’t have a suitable id or name attribute for the element

  • XPath uses path expressions to identify and navigate nodes in an XML document

  • Can be used in absolute or relative terms
#locate the login form element
login_form_absolute = driver.find_element_by_xpath("/html/body/form[1]")
login_form_relative = driver.find_element_by_xpath("//form[1]")
login_form_id = driver.find_element_by_xpath("//form[@id='loginForm']")

#locate the username element
username = driver.find_element_by_xpath("//form/input[@name='username']")
username = driver.find_element_by_xpath("//form[@id='loginForm']/input[1]")
username = driver.find_element_by_xpath("//input[@name='username']")

Locating by xpath

Locating elements

  • Use the class tag to find elements

  • These classnames are used to point to a class in a style sheet

#Find by class name
content = driver.find_element_by_class_name('content')

Locating by class

Page Interaction

  • Finding an element on a page
  • Interacting with the element
#Finding an element
search = driver.find_element_by_name('q');

#Interacting with the element
search.clear();
search.send_keys("pycon");
search.send_keys(Keys.RETURN);

Filling forms

  • Selecting and deselecting options
  • All options
  • Submitting a form 
from selenium.webdriver.support.ui import Select
#Selecting options
select= Select(driver.find_element_by_name('numReturnSelect'))
select.select_by_index(4)
select.select_by_visible_text("200")
select.select_by_value("250")
#Deselecting options
select.deselect_all()
#All options
options = select.options
#Submitting 
submit_button = driver.find_element_by_name('continue')
submit_button.submit();

Drag and Drop

  • Select the source and destination element
  • Drag and drop using ActionChains
  • Drag and drop by Offset and from source to target
from selenium.webdriver import ActionChains
action_chains= ActionChains(driver)
#Locate source element
source= driver.find_element_by_id('draggable')
#Locate target element
target = driver.find_element_by_id('droppable')
#Drag and drop by offset
action_chains.drag_and_drop_by_offset(source, 100, 100).perform()
#Drag and drop from source to target
action_chains.drag_and_drop(source, target).perform()

Waits

  • The elements in a webpage may be loaded at different time intervals due to AJAX calls

  • While locating elements on a page, the locate function will raise a ‘ElementNotVisibleException’ if the element has not been loaded into the DOM at that point of time.

  • Waiting adds a time interval between actions performed by the WebDriver

  • 2 types- explicit and implicit

Waits - Implicit

  • Polls the DOM for a certain amount of time when trying to find an element or elements if they are not immediately available.

  • The waiting time is specified in seconds

from selenium import webdriver

driver = webdriver.Firefox()
driver.implicitly_wait(10) # seconds
driver.get("http://somedomain/url_that_delays_loading")
myDynamicElement = driver.find_element_by_id("myDynamicElement")

Waits - Explicit

  • Pause until a certain condition has been satisfied

  • Use a combination of the classes WebDriverWait and Expected Condition to add explicit waits.

try:
    element = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.ID, "myDynamicElement"))
    )
finally:
    driver.quit()

Waits - Conditions

  1. title_is
  2. title_contains
  3. visibility_of
  4. presence_of_all_elements_located
  5. text_to_be_present_in_element
  6. text_to_be_present_in_element_value
  7. frame_to_be_available_and_switch_to_it
  8. invisibility_of_element_located
  9. element_to_be_clickable - it is Displayed and Enabled.
  10. element_located_selection_state_to_be
  11. alert_is_present

Best Practices

  • Figure out what works best for you
  • Variables naming convention [ _ and ()]
  • Separating action and intent
  • there is no single 'best' approach
  • agile, iterative, incremental approach
  • keep selenium up to date
  • Practice
  • Hack around

Recap

  • The need for automated testing
  • Mike Cohn's test automation pyramid
  • Python Selenium bindings
  • Locating elements by id, name, xpath and class
  • Navigating through pages - Page interaction, filling forms, drag and drop
  • Waits - implicit and explicit

Resources used:

      http://selenium-python.readthedocs.io/

      learnpythonthehardway

Python Automation and Testing course on LinkedIn Learning

Thank You!

Questions?

@abhi12ravi

@myriadbhoom

bhoomika10@gmail.com

abhi12ravi@gmail.com

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