Writing automation tests with python selenium behave pageobjects

Writing automated tests
Python + Selenium
Letícia Rostirola

Before Automating: BDD
● Encouraging conversation between all involved
● Writing down examples to make things clearer
● Reduce ambiguity
“Automating the scenarios resulting from the conversations is an optional next step.”
Julien Biezemans
Creator of Cucumber.js

Gherkin: a natural language style
“Gherkin is designed to be easy to learn by non-
programmers, yet structured enough to allow
concise description of examples to illustrate
business rules in most real-world domains”.

Why Test Automation?
● Saves you time, money and people
● Consistency of tests
● Continuous Integration
● Avoid boredom

Cucumber
Cucumber can be used to implement automated tests based
on scenarios described in your Gherkin feature files.
In the example given in step definitions:
When she eats 3 cucumbers
Cucumber extracts the text 3 from the step, converts it to an
int and passes it as an argument to the method.

Cucumber vs Behave vs Godog
Cucumber: Java, JS, Ruby.
Behave: Cucumber Python style.
Godog: Cucumber for golang.

Web browser automation
Selenium
“Selenium automates browsers. That's it! What you do with
that power is entirely up to you”.

Web browser automation
Selenium vs Splinter

Page Objects design pattern
“Despite the term "page" object, these objects shouldn't usually be built for each page, but rather for
the significant elements on a page. So a page showing multiple albums would have an album list
page object containing several album page objects. There would probably also be a header page
object and a footer page object.”
Martin Fowler
Software Developer

Page Objects: Benefits
● Create reusable code that can be shared
across multiple test cases
● Reduce the amount of duplicated code
● If the user interface changes, the fix needs
changes in only one place

Page Objects: Example
from lib.pages.basepage import BasePage
from selenium.webdriver.common.by import By
class LogoutPage(BasePage):
def __init__(self, context):
BasePage.__init__(self, context.browser, base_url='http://twitter.com/logout')
locator_dictionary = {
"submit" : (By.CSS_SELECTOR, 'button[type="submit"]'),
}

Page Objects: BasePage
class BasePage(object):
base_url = 'http://twitter.com/'
def __init__(self, driver):
self.driver = driver
def find(self, selector):
return self.driver.find_element_by_css_selector(selector)
def contains_content(self, text, timeout):
try:
elem = WebDriverWait(self.driver, timeout).until(
EC.text_to_be_present_in_element((By.TAG_NAME, 'body'), text))
return elem
except TimeoutException as ex:
return False

Tree
https://github.com/ladylovelace/automation-behave-pageobjects
.
├── features
│ ├── config.py
│ ├── config.py.dist
│ ├── environment.py
│ ├── lib
│ │ ├── chromedriver
│ │ └── pages
│ │ ├── basepage.py
│ │ ├── homepage.py
│ │ └── loginpage.py
│ ├── login_twitter.feature
│ ├── steps
│ │ ├── home.py
│ │ └── login.py
│ └── tweet.feature
├── README.md
├── requirements.txt
├── screenshot

Features
Feature: Tweet
Allow valid users
Post 280 characters limit per tweet
To have a better day
@rainy
Scenario: Tweet like a crazy teenager > 280 chars
Given the valid user is logged in on the homepage
When user post invalid tweet
Then the tweet button should be disabled
@sunny @sanity
Scenario: Tweet properly <= 280 chars
Given the valid user is logged in on the homepage
When user post valid tweet
Then the tweet button should be enabled
And the user should be able to tweet

environment.py
import os
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
from lib.pages.basepage import BasePage
def before_all(context):
driver = webdriver.Chrome()
driver.maximize_window()
driver.implicitly_wait(10)
context.browser = BasePage(driver)
def after_scenario(context, scenario):
context.browser.screenshot(str(scenario))
def after_all(context):
print("===== That's all folks =====")
context.browser.close()

steps/page.py
from features.lib.pages.loginpage import LoginPage
from behave import given, when, then
from config import USER
@when(u'the "{user_type}" user logs in')
def login(context, user_type):
username_field = context.browser.find(
LoginPage.locator_dictionary['email'])
password_field = context.browser.find(
LoginPage.locator_dictionary['password'])
username_field.send_keys(USER[user_type]['email'])
password_field.send_keys(USER[user_type]['pass'])
submit_button = context.browser.find(
LoginPage.locator_dictionary['submit'])
submit_button.click()
Scenario: Valid login
Given "valid" user navigates to page "landing"
When the "valid" user logs in
Then the user should be redirected to homepage
feature/steps/login.py feature/steps/login.py

config.py (optional)
USER = {
'valid': {
'email': 'YOUR_EMAIL',
'pass': 'YOUR_PASS',
'username': 'YOUR_USERNAME',
},
'invalid': {
'email': 'spy@spy.com.br',
'pass': 'mudar123',
},
}

Running
https://github.com/PyLadiesSanca/little-monkey

$ pip install selenium
$ pip install behave
$ behave

Tips
● Be aware of Chromedriver/chrome version
○ Chrome headless requires chromedriver 2.3+
● Use Selenium explicit/implicit wait instead of python time.sleep function
○ Better, faster and stronger
● Use find_by_id (or similar) instead of find_by_xpath
○ IE provides no native XPath-over-HTML solution

Best Practices
● "Tag" parts of your feature file
● Gherkin common mistakes
○ Using absolute values instead of configurable values
○ Describing every action instead of a functionality
○ Writing scripts in first person instead of third person
● Good relationship with Frontenders > You will need IDs
● The scenarios should run independently, without any dependencies on other scenarios

References
https://docs.cucumber.io/bdd/overview/
http://www.seleniumhq.org/
https://docs.cucumber.io
https://martinfowler.com/bliki/PageObject.html
https://selenium-python.readthedocs.io/page-objects.html
http://www.seleniumframework.com/python-frameworks/modeling-page-objects/
https://behave.readthedocs.io/en/latest/practical_tips.html
http://www.seleniumframework.com/python-frameworks/complete-the-workflow/
https://www.infoq.com/br/news/2015/07/bdd-cucumber-testing

Writing automation tests with python selenium behave pageobjects

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