Cucumber + Capybara What we need for rails integration test

What’s Capybara

Capybara is a webrat alternative which aims to support all browser simulators.

As you know, webrat can not run javascript on the webpage. In order to test javascript and AJAX based website we need install Selenium-clientgithub.com/ph7/selenium-client and learn extra API and also some configuratons.

Capybara give your a full stack solution.
You can use similar API drive webrat and selenium. And don’t need worry about configuraton.

What’s more, Capybara integrated Celerity which is a JRuby wrapper around HtmlUnit - a headless Java browser with JavaScript support. As your expect it using the same API.

And the killer feature of Capybara is you can easily change driver it use for testing. Not only in config file but also in runtime.

Why we need Cucumber

Before I introduce what is Cucumber, you need know what is BDD.

BDD is an evolution thinking behind TestDrivenDevelopment and AcceptanceTestDrivenPlanning

You don’t need worry about what the hell BDD is. After you start using Cucumber you will know. I promise.

Cucumber is allow you execute plain-text which written by BDD like format as automated tests.

There are plenty of materials on the internet which you can learn Cucumber

First place your need go is Ryan Bates’ RailsCasts Beginning with Cucumber
Then official Wiki of Cucumber will very helpful!!, and there also list some blog posts written by community

I won’t involve more about it. In my later blog post I will give you some tricks about using Cucumber.

Using Cucumber and Capybara

Install

Follow the instruction on Capybara:

Install as a gem

sudo gem install capybara

On OSX you may have to install libffi, you can install it via MacPorts with:

sudo port install libffi

And you also need install Cucumber

sudo gem install cucumber

Generate basic Cucumber folder structure and configuratons

Capybara is built to work nicely with Cucumber. You can easily generate Capybara style cucumber structure and configuraton.

script/generate cucumber --capybara

And maybe you also need install another gem named launchy which is helper class for launching cross-platform applications in a fire and forget manner.

sudo gem install launchy

group :cucumber do
  gem 'capybara'
  gem 'database_cleaner'
  gem 'cucumber-rails'
  gem 'cucumber'
  gem 'rspec-rails'
  gem 'spork'
  gem 'launchy'    # So you can do Then show me the page
end 

Configuration

Available Configuration

Actually after you run the generator, you don’t need much more configuraton. Here I’ll list some of configuraton you can set.

You can specify it in features/support/env.rb file

Capybara.run_server = true #Whether start server when testing
Capybara.default_selector = :xpath #default selector , you can change to :css
Capybara.default_wait_time = 2 #When we testing AJAX, we can set a default wait time
Capybara.ignore_hidden_elements = false #Ignore hidden elements when testing, make helpful when you hide or show elements using javascript
Capybara.javascript_driver = :culerity #default driver when you using @javascript tag

Load rails test features

You can put codes below in features/support/env.rb file

Before do
  Fixtures.reset_cache
  fixtures_folder = File.join(RAILS_ROOT, 'test', 'fixtures')
  fixtures = Dir[File.join(fixtures_folder, '*.yml')].map {|f| File.basename(f, '.yml') }
  Fixtures.create_fixtures(fixtures_folder, fixtures)
end

And change

Cucumber::Rails::World.use_transactional_fixtures = false
DatabaseCleaner.strategy = :truncation

OK. For now we already finish configuration. we can start writing cucumber test

How to run test under different testing driver

As you know cucumber support tags
Capybara using tag to specify different driver, it supports @javascript, @selenium, @celerity, @culerity and @rack_test tags
You can use it like:

  @javascript
  Scenario: do something AJAXy
  When I click the AJAX link
  ...

About how to write cucumber, you can check out Cucumber Wiki

About Capybara API

What I want to show you is how’s Capybara API look like.

This is all support Webrat like APIs in Capybara

DSL_METHODS = [
      :all, :attach_file, :body, :check, :choose, :click, :click_button, :click_link, :current_url, :drag, :evaluate_script,
      :field_labeled, :fill_in, :find, :find_button, :find_by_id, :find_field, :find_link, :has_content?, :has_css?,
      :has_no_content?, :has_no_css?, :has_no_xpath?, :has_xpath?, :locate, :save_and_open_page, :select, :source, :uncheck,
      :visit, :wait_until, :within, :within_fieldset, :within_table, :has_link?, :has_no_link?, :has_button?, :has_no_button?,
      :has_field?, :has_no_field?, :has_checked_field?, :has_unchecked_field?, :has_no_table?, :has_table?, :unselect,
      :has_select?, :has_no_select?
    ]

Here are some examples which are not mentioned in Capybara Wiki.

  # we can get page object from cucumber steps, page is an instance of @Capybara::Session@
  page.has_css? "ul.error_messages li", :count => 5, :text => "error"
  page.has_xpath? "//ul[@class='error_messages']/li", :count => 5, :text => "error"

  #Equivalent
  page.find(:css,"ul.error_messages li", :count => 5, :text => "error"
  page.find(:xpath,"//ul[@class='error_messages']/li", :count => 5, :text => "error"

  #Iterate all elements you found
  all(:xpath,"//ul[@class='error_messages']/input").each do |node|
    puts node.value
    puts node.[:attribute_name]
    puts node.click
    puts node.set("aa") #set value
    puts node.text
  end

XPath

If you want to use XPath in Capybara, you need caution string escape.
Capybara give us a good example

def s(string)
  if string.include?("'")
    string = string.split("'", -1).map do |substr|
    "'#{substr}'"
    end.join(%q{,"'",})
    "concat(#{string})"
  else
    "'#{string}'"
  end
end

Summarize

Cucumber + Capybara will make your integration test easilier.
Finally we find a full stack integration test.
Have fun with it!

from : http://www.allenwei.cn/cucumber-capybara-what-we-need-for-rails-integration-test