CSC/ECE 517 Spring 2014/ch1a 1j sr

Background

Watir, pronounced water, is an open-source (BSD) family of Ruby libraries for automating web browsers. It allows you to write tests that are easy to read and maintain. It is simple and flexible. Watir drives browsers the same way people do. It clicks links, fills in forms, presses buttons. Watir also checks results, such as whether expected text appears on the page. Watir is a family of Ruby libraries but it supports your app no matter what technology it is developed in. Whilst Watir supports only Internet Explorer on Windows, Watir-WebDriver supports Chrome, Firefox, Internet Explorer, Opera and also running in headless mode (HTMLUnit).

Examples

Here's Watir in action. Like all ruby gems, it has to be included to be used. Including Watir gem to drive Internet Explorer on Windows

require 'watir'

Including Watir-WebDriver gem to drive Firefox/Chrome on Windows/Mac/Linux

require 'watir-webdriver'

After including it, It can be used simply. For example to start a new browser & and going to Watir's demo website:

browser = Watir::Browser.new
browser.goto 'http://bit.ly/watir-example'

For setting the value of a text field

browser.text_field(:name => 'entry.0.single').set 'Watir'

For setting a multi-line text box

browser.text_field(:name => 'entry.1.single').set "I come here from Australia. \n The weather is great here."

Their official example page has a few examples.

Features

The following two sections discuss Watir's features in relation to other frameworks that are used currently.

Watir Compared to Capybara

On their blog, Watir team makes an interesting comparison of Capybara with Watir.

Basically, there are three ways, that is, three levels of details and control, that a programmer has to simulate a browser and the actions a user performs with an app in the browser. These three ways are selenium-webdriver API,watir-webdriver API and Capybara DSL <ref> http://watirmelon.com/tag/capybara/ </ref>.

Each level has it's pros and cons. While the lower level (Selenium) facilitate more control and flexibility, the higher level (Capybara) is convenient and quick to use and get up and running. Watir is somewhere in the middle.

The author uses the analogy of buying raw animal carcass, beef cuts, and prepared meats such as sausages to show the relationship between these three ways of interaction with the app.

Let's consider an example:

Example taken from this page. If we want to accomplish a fairly basic scenario on this example Google Doc form:

Start a browser

Navigate to the watir-webdriver-demo form
Check whether text field with id ‘entry_0′ exists (this should exist)
Check whether text field with id ‘entry_99′ exists (this shouldn’t exist)
Set a text field with id ‘entry_0′ to ’1′
Set a text field with id ‘entry_0′ to ’2′
Select ‘Ruby’ from select list with id ‘entry_1′
Click the Submit button

# * Start browser
# * Navigate to watir-webdriver-demo form
# * Check whether text field with id 'entry_0' exists
# * Check whether text field with id 'entry_99' exists
# * Set text field with id 'entry_0' to '1'
# * Set text field with id 'entry_0' to '2'
# * Select 'Ruby' from select list with id 'entry_1'
# * Click the Submit button
 
require 'bench'
 
benchmark 'selenium-webdriver' do
  require 'selenium-webdriver'
 
  driver = Selenium::WebDriver.for :firefox
  driver.navigate.to 'http://bit.ly/watir-webdriver-demo'
  begin
    driver.find_element(:id, 'entry_0')
  rescue Selenium::WebDriver::Error::NoSuchElementError
    # doesn't exist
  end
  begin
    driver.find_element(:id, 'entry_99').displayed?
  rescue Selenium::WebDriver::Error::NoSuchElementError
    # doesn't exist
  end
  driver.find_element(:id, 'entry_0').clear
  driver.find_element(:id, 'entry_0').send_keys '1'
  driver.find_element(:id, 'entry_0').clear
  driver.find_element(:id, 'entry_0').send_keys '2'
  driver.find_element(:id, 'entry_1').find_element(:tag_name => 'option', :value => 'Ruby').click
  driver.find_element(:name, 'submit').click
  driver.quit
end
 
benchmark 'watir-webdriver' do
  require 'watir-webdriver'
  b = Watir::Browser.start 'bit.ly/watir-webdriver-demo', :firefox
  b.text_field(:id => 'entry_0').exists?
  b.text_field(:id => 'entry_99').exists?
  b.text_field(:id => 'entry_0').set '1'
  b.text_field(:id => 'entry_0').set '2'
  b.select_list(:id => 'entry_1').select 'Ruby'
  b.button(:name => 'submit').click
  b.close
end
 
benchmark 'capybara' do
  require 'capybara'
  session = Capybara::Session.new(:selenium)
  session.visit('http://bit.ly/watir-webdriver-demo')
  session.has_field?('entry_0') # => true
  session.has_no_field?('entry_99') # => true
  session.fill_in('entry_0', :with => '1')
  session.fill_in('entry_0', :with => '2')
  session.select('Ruby', :from => 'entry_1')
  session.click_button 'Submit'
  session.driver.quit
end
 
run 10

As we can see from the above code that:

Watir allows a little bit more neatness, for example, we don't have to write full URLs, complete with http://
At the same time, it give enough power to specify the selectors explicitly. For example Capybara only supports name, id and label, but you can’t tell fill_in which specific one to choose: it appears to try each selector one by one until it finds it.

Watir Compared to Cucumber

Cucumber and Watir are not comparable in the sense that they are both different tools that aid each other for the same goal simple behavior-driven unit testing of the app. As demonstrated in the example, Watir is used to manipulate the browser, while Cucumber is used to write business readable unit tests. On its website, Cucumber mentions these six steps for suing Cucumber:

Describe behaviour in plain text
Write a step definition in Ruby
Run and watch it fail
Write code to make the step pass
Run again and see the step pass
Repeat 2-5 until green like a cuke

Basically "Cucumber lets software development teams describe how software should behave in plain text. The text is written in a business-readable domain-specific language and serves as documentation, automated tests and development-aid - all rolled into one format."

In its community wiki Cucumber mentions the usage of Watir (or Selenium, a similar tool) for making transactions with the browser. So these two tools go hand in hand in order to write a complete successful automated unit test suit, one that can be readable by non-technical people as well. Consider the following example:

Example

The way Cucumber works is that after installing the gem, the steps in business readable form are stored in .feature file, and then actual steps are written in the step definitions file. As you can see in the example below, the step definitions can then use Watir to make transactions with the browser.

features/example.feature

Feature: Search In order to use Google users must be able to search for content 
  Scenario: Search for a term
    Given I have entered "watir" into the query
    When I click "search"
    Then I should see some results

features/step_definitions/example_steps.rb

require "watir-webdriver"
require "rspec/expectations"
 
Given /^I have entered "([^"]*)" into the query$/ do |term|
  @browser ||= Watir::Browser.new :firefox
  @browser.goto "google.com"
  @browser.text_field(:name => "q").set term
end
 
When /^I click "([^"]*)"$/ do |button_name|
  @browser.button.click
end
 
Then /^I should see some results$/ do
  @browser.div(:id => "resultStats").wait_until_present
  @browser.div(:id => "resultStats").should exist 
  @browser.close
end

Important Terms

References