johnpfeiffer

Selenium headless browser automated testing with PhantomJS and Python

Why Automated Testing

Automated Testing is critical to maintaining quality while increasing velocity (aka avoiding being crushed to death by technical debt). Web sites are inherently complex to test:

  • requires a client and server,
  • combination of UI and Logic,
  • lots of paths,
  • etc

A challenge facing the HipChat team is how to maintain quality while supporting both SaaS and BTF versions, expanding the team, increasing the functionality, and experiment with architecture (or even just normal bug fixing refactoring).

Choosing Selenium

Continued innovation by the Selenium project has created a stable and usable programmatic interface such that clicking on different components in a web page can be automated.

Selenium tests can be generated manually by a Firefox plugin https://docs.seleniumhq.org/projects/ide/ and then saved to a .html file which is helpful in that it can be done by non programmers. Eessentially selenium as a Domain Specific Language creates artifacts rather than tribal knowledge.

The Selenium Documentation is overly complicated by legacy versions just use the IDE, play with the record button and click on stuff, save the .html, and analyze and you'll quickly get the hang of it.

Example Selenium Test HTML

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head profile="http://selenium-ide.openqa.org/profiles/test-case">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<link rel="selenium.base" href="https://mysite.com/" />
<title>selenium-login</title>
</head>
<body>
    <table cellpadding="1" cellspacing="1" border="1">
    <thead>
    <tr><td rowspan="1" colspan="3">selenium-login</td></tr>
    </thead><tbody>
    <tr>
    <td>open</td>
    <td>/</td>
    <td></td>
    </tr>
    <tr>
    <td>type</td>
    <td>id=email</td>
    <td>[email protected]</td>
    </tr>
    <tr>
    <td>type</td>
    <td>id=password</td>
    <td>examplepassword</td>
    </tr>
    <tr>
    <td>clickAndWait</td>
    <td>id=signin</td>
    <td></td>
    </tr>
    <tr>
    <td>assertLocation</td>
    <td>https://mysite.com/home</td>
    <td></td>
    </tr>
    <tr>
    <td>assertElementPresent</td>
    <td>link=Launch the web app</td>
    <td></td>
    </tr>
    </tbody></table>
</body>
</html>

To get started with the IDE automation framework for interactions with websites (like a programmatic browser) http://docs.seleniumhq.org/docs/02_selenium_ide.jsp#introduction

Selenium WebDriver

Characteristics of good test plans are focusing on "happy path" high value tests, avoiding fragility/brittleness (any change invalidates many tests), and of course avoiding manual intervention.

Having a huge suite of IDE based tests incurs potentially unsustainable technical testing debt (e.g. investigating/rewriting why/when many tests fail).

And requiring a testing machine with a UI with a browser etc. is a lot of overhead if you intend on (correctly!) running the tests really often.

Converting raw .html tests to a specific language binding (i.e. moving more to WhiteBox) can remove non essential parts of the test and increase flexibility (multiple browsers!).

sudo pip install selenium

installation assuming linux and python

Example Selenium Python Webdriver

The IDE helpfully not only can save a Test but can File -> Export Test Case As -> python

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support.ui import Select
from selenium.common.exceptions import NoSuchElementException
import unittest, time, re


class SeleniumLogin(unittest.TestCase):
def setUp(self):
    self.driver = webdriver.Firefox()
    self.driver.implicitly_wait(30)
    self.base_url = "https://mysite.com/"
    self.verificationErrors = []
    self.accept_next_alert = True

def test_selenium_login(self):
    driver = self.driver
    driver.get(self.base_url + "/")
    driver.find_element_by_id("email").clear()
    driver.find_element_by_id("email").send_keys("[email protected]")
    driver.find_element_by_id("password").clear()
    driver.find_element_by_id("password").send_keys("examplepassword")
    driver.find_element_by_id("signin").click()
    self.assertEqual("https://mysite.com/home", driver.current_url)
    self.assertTrue(self.is_element_present(By.LINK_TEXT, "Launch the web app"

def is_element_present(self, how, what):
    try: self.driver.find_element(by=how, value=what)
    except NoSuchElementException, e: return False
    return True

def is_alert_present(self):
    try: self.driver.switch_to_alert()
    except NoAlertPresentException, e: return False
    return True

def close_alert_and_get_its_text(self):
    try:
    alert = self.driver.switch_to_alert()
    alert_text = alert.text
    if self.accept_next_alert:
        alert.accept()
    else:
    alert.dismiss()
    return alert_text
    finally: self.accept_next_alert = True

def tearDown(self):
    self.driver.quit()
    self.assertEqual([], self.verificationErrors)


if __name__ == "__main__":
unittest.main()

python selenium-login.py runs the tests (opens Firefox, executes all of the commands)

Docs for the webdriver interface:

useful for looking up things like driver.current_url

Selenium Performance with PhantomJS

Removing the UI requirement improves test performance and increases the options of where the test is run (Dev machines, headless VMs, cloud servers, etc.)

Installing the python selenium library, downloading the phantomJS binary running it was relatively easy with Ubuntu Linux since the project integrated GhostDriver too.

The phantomjs headless browser http://phantomjs.org Archived as of 2018-03 and no longer under active development

Installing PhantomJS

Archived as of 2018-03 and no longer under active development http://phantomjs.org/download.html

For example for Linux one might use:

wget <https://bitbucket.org/ariya/phantomjs/downloads/phantomjs-1.9.8-linux-x86_64.tar.bz2>
tar -xjvf phantomjs-1.9.8-linux-x86_64.tar.bz2

Example PhantomJS webdriver python script

mini script to just show usage

from selenium import webdriver

driver = webdriver.PhantomJS(executable_path='/opt/phantomjs-1.9.8-linux-x86_64/bin/phantomjs', port=9134)
driver.get("http://127.0.0.1")
print driver.current_url
driver.quit
print "done"

To run the phantomJS binary phantomjs-1.9.8-linux-x86_64/bin/phantomjs --webdriver=9134

ghostdriver included and running on port 9134

As an example I found PhantomJS to be at least twice as fast as Firefox ./phantomjs --webdriver=127.0.0.1:9134 --ignore-ssl-errors=true

skip verifying SSL

Advanced Python and PhantomJS example

more complete example with python unittest framework (used the Firefox Selenium IDE plugin -> Export)

logs in, asserts there is an Admin tab which when clicked shows Group Info

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support.ui import Select
from selenium.common.exceptions import NoSuchElementException
import unittest, time, re

class SeleniumAdminLogin( unittest.TestCase ):

    def setUp( self ):
        self.driver = webdriver.PhantomJS( '/opt/phantomjs-1.9.2-linux-x86_64/bin/phantomjs', port=9134 )
        self.driver.implicitly_wait(30)
        self.base_url = "https://myexample.org"
        self.verificationErrors = []
        self.accept_next_alert = True

    def test_selenium_admin_login( self ):
        driver = self.driver
        driver.get( self.base_url + "/" )
        driver.find_element_by_id( "email" ).clear()
        driver.find_element_by_id( "email" ).send_keys( "[email protected]" )
        driver.find_element_by_id( "password" ).clear()
        driver.find_element_by_id( "password" ).send_keys( "mypassword" )
        driver.find_element_by_id( "signin" ).click()
        self.assertEqual("https://myexample.org/home", driver.current_url)
        self.assertTrue(self.is_element_present(By.LINK_TEXT, "Launch the web app"))
        self.assertTrue(self.is_element_present(By.CSS_SELECTOR, "a.admin > span"))
        driver.find_element_by_css_selector("a.admin > span").click()
        self.assertEqual("Group Info", driver.find_element_by_css_selector("h1").text)

    def is_element_present(self, how, what):
        try: 
            self.driver.find_element(by=how, value=what)
        except NoSuchElementException, e: return False
            return True

    def is_alert_present(self):
        try: 
            self.driver.switch_to_alert()
        except NoAlertPresentException, e: return False
        return True

    def close_alert_and_get_its_text(self):
        try:
            alert = self.driver.switch_to_alert()
            alert_text = alert.text
            if self.accept_next_alert:
                alert.accept()
            else:
                alert.dismiss()
            return alert_text
            finally: 
                self.accept_next_alert = True

    def tearDown(self):
        self.driver.quit()
        self.assertEqual([], self.verificationErrors)

if __name__ == "__main__":
    unittest.main()

Basic Polling with Firefox and Mac

import datetime
import os
import sys
import time
import urllib2

from selenium import webdriver
from selenium.webdriver.firefox.firefox_binary import FirefoxBinary


FIREFOX_MAC_PATH = '/Applications/Firefox.app/Contents/MacOS/firefox-bin'
G_URL = 'https://g.example.com'

if __name__ == '__main__':

    if len(sys.argv) < 2:
        print('Usage error: requires a username')
        sys.exit(1)
    print(sys.argv)
    username = sys.argv[1]

    # https://docs.python.org/2/library/datetime.html#strftime-strptime-behavior
    new_server_name = datetime.datetime.now().strftime('%d%b%H%M%S').lower()

    if os.path.exists(FIREFOX_MAC_PATH):
        driver = FirefoxBinary(firefox_path=FIREFOX_MAC_PATH)
    else:
        driver = webdriver.Firefox()

    driver.get(G_URL)
    print(driver.current_url)
    if driver.current_url.endswith('login'):
        driver.find_element_by_name('username').clear()
        driver.find_element_by_name('username').send_keys(username)
        driver.find_element_by_css_selector('input[type="submit"]').click()

    driver.get('{}/deploy/simple_server'.format(G_URL))
    driver.find_element_by_name('name').clear()
    driver.find_element_by_name('name').send_keys('{}-{}'.format(username, new_server_name))
    driver.find_element_by_name('hostname').clear()
    driver.find_element_by_name('hostname').send_keys('{}-{}'.format(username, new_server_name))
    driver.find_element_by_css_selector('input[type="submit"]').click()
    url = 'https://{}-{}.example.com'.format(username, new_server_name)

    print('requested build of {}'.format(url))
    for _ in xrange(20):
        status_code = 404
        try:
            connection = urllib2.urlopen(urllib2.Request(url))
            status_code = connection.getcode()
            content = connection.read()
        except Exception as error:
            print('waiting for {}'.format(url))

        if status_code == 200:
            break
        time.sleep(30)

    driver.get(url)
    print(driver.current_url)
    print(driver.title)
    driver.quit()
    print('done')

More Info https://realpython.com/headless-selenium-testing-with-python-and-phantomjs/

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