Capybara

github.com/jnicklas/capybara

Description:

Capybara aims to simplify the process of integration testing Rack applications, such as Rails, Sinatra or Merb. It is inspired by and aims to replace Webrat as a DSL for interacting with a webapplication. It is agnostic about the driver running your tests and currently comes bundled with rack-test, Culerity, Celerity and Selenium support built in. env.js support is available as the capybara-envjs gem.

Online documentation is availbable at rdoc.info.

Install:

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

Development:

Source hosted at GitHub.
Please direct questions, discussions at the mailing list.
Report issues on GitHub Issues

Pull requests are very welcome! Make sure your patches are well tested, Capybara is a testing tool after all. Please create a topic branch for every separate change you make.

Capybara uses bundler in development. To set up a development environment, simply do:

gem install bundler --pre
bundle install

Using Capybara with Cucumber

Capybara is built to work nicely with Cucumber. The API is very similar to Webrat, so if you know Webrat you should feel right at home. Support for Capybara is built into cucumber-rails 0.2. In your Rails app, just run:

script/generate cucumber --capybara

And everything should be set up and ready to go.

If you want to use Capybara with Cucumber outside Rails (for example with Merb or Sinatra), you’ll need to require Capybara and set the Rack app manually:

require 'capybara/cucumber'
Capybara.app = MyRackApp

Now you can use it in your steps:

When /I sign in/ do
  within("#session") do
    fill_in 'Login', :with => '[email protected]'
    fill_in 'Password', :with => 'password'
  end
  click_link 'Sign in'
end

Default and current driver

You can set up a default driver for your features. For example if you’d prefer to run Selenium, you could do:

require 'capybara/rails'
require 'capybara/cucumber'
Capybara.default_driver = :selenium

You can change the driver temporarily:

Capybara.current_driver = :culerity
Capybara.use_default_driver

You can do this in Before and After blocks to temporarily switch to a different driver. Note that switching driver creates a new session, so you may not be able to switch in the middle of a Scenario.

Cucumber and Tags

Capybara sets up some tags for you to use in Cucumber. Often you’ll want to run only some scenarios with a driver that supports JavaScript, Capybara makes this easy: simply tag the scenario (or feature) with @javascript:

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

You can change which driver Capybara uses for JavaScript:

Capybara.javascript_driver = :culerity

There are also explicit @selenium, @culerity and @rack_test tags set up for you.

Selenium

At the moment, Capybara supports Webdriver, also called Selenium 2.0, not Selenium RC. Provided Firefox is installed, everything is set up for you, and you should be able to start using Selenium right away.

If desired, you can change Selenium browser to :chrome or :ie:

require "selenium-webdriver"
Selenium::WebDriver.for :chrome

Celerity

Celerity only runs on JRuby, so you’ll need to install the celerity gem under JRuby:

jruby -S gem install celerity

Note that some specs currently fail on celerity 0.7.5, due to a bug in recent versions of HTMLUnit. It is recommended you use celerity 0.7.4 for the time being.

Culerity

Install celerity as noted above, make sure JRuby is in your path. Note that Culerity doesn’t seem to be working under Ruby 1.9 at the moment.

env.js

The capybara-envjs driver uses the envjs gem (GitHub, rubygems.org) to interpret JavaScript outside the browser. The driver is installed by installing the capybara-envjs gem:

gem install capybara-envjs

More info about the driver and env.js are available through the links above. The envjs gem only supports Ruby 1.8.7 at this time.

The DSL

Capybara’s DSL is inspired by Webrat. While backwards compatibility is retained in a lot of cases, there are certain important differences.

Unlike in Webrat, all searches in Capybara are *case sensitive*. This is because Capybara heavily uses XPath, which doesn’t support case insensitivity.

Navigating

You can use the visit method to navigate to other pages:

visit('/projects')
visit(post_comments_path(post))

The visit method only takes a single parameter, the request method is always GET.

You can get the current path of the browsing session for test assertions:

current_path.should == post_comments_path(post)

Clicking links and buttons

You can interact with the webapp by following links and buttons. Capybara automatically follows any redirects, and submits forms associated with buttons.

click_link('id-of-link')
click_link('Link Text')
click_button('Save')
click_link_or_button('Link Text')
click_link_or_button('Button Value')

Interacting with forms

Forms are everywhere in webapps, there are a number of tools for interacting with the various form elements:

fill_in('First Name', :with => 'John')
fill_in('Password', :with => 'Seekrit')
fill_in('Description', :with => 'Really Long Text…')
choose('A Radio Button')
check('A Checkbox')
uncheck('A Checkbox')
attach_file('Image', '/path/to/image.jpg')
select('Option', :from => 'Select Box')

Querying

Capybara has a rich set of options for querying the page for the existence of certain elements, and working with and manipulating those elements.

page.has_xpath?('//table/tr')
page.has_css?('table tr.foo')
page.has_content?('foo')

You can these use with RSpec’s magic matchers:

page.should have_xpath('//table/tr')
page.should have_css('table tr.foo')
page.should have_content('foo')
page.should have_no_content('foo')

Note that page.should have_no_xpath is preferred over page.should_not have_xpath. Read the section on asynchronous JavaScript for an explanation.

Finding

You can also find specific elements, in order to manipulate them:

find_field('First Name').value
find_link('Hello').visible?
find_button('Send').click

find(:xpath, "//table/tr").click
find("#overlay").find("h1").click
all('a').each { |a| a[:href] }

Note that find will wait for an element to appear on the page, as explained in the AJAX section. If the element does not appear it will raise an error.

These elements all have all the Capybara DSL methods available, so you can restrict them to specific parts of the page:

find('#navigation').click_link('Home')
find('#navigation').should have_button('Sign out')

Scoping

Capybara makes it possible to restrict certain actions, such as interacting with forms or clicking links and buttons, to within a specific area of the page. For this purpose you can use the generic within method. Optionally you can specify which kind of selector (CSS or XPath to use).

within("//li[@id='employee']") do
  fill_in 'Name', :with => 'Jimmy'
end

within(:css, "li#employee") do
  fill_in 'Name', :with => 'Jimmy'
end

You can choose which kind of selector Capybara uses by default, by setting Capybara.default_selector.

There are special methods for restricting the scope to a specific fieldset, identified by either an id or the text of the fieldet’s legend tag, and to a specific table, identified by either id or text of the table’s caption tag.

within_fieldset('Employee') do
  fill_in 'Name', :with => 'Jimmy'
end

within_table('Employee') do
  fill_in 'Name', :with => 'Jimmy'
end

Scripting

In drivers which support it, you can easily execute JavaScript:

page.execute_script("$('body').empty()")

For simple expressions, you can return the result of the script. Note that this may break with more complicated expressions:

result = page.evaluate_script('4 + 4');

Debugging

It can be useful to take a snapshot of the page as it currently is and take a look at it:

save_and_open_page

Asynchronous JavaScript (AJAX and friends)

When working with asynchronous JavaScript, you might come across situations where you are attempting to interact with an element which is not yet present on the page. Capybara automatically deals with this by waiting for elements to appear on the page.

When issuing instructions to the DSL such as:

click_link('foo')
click_link('bar')
page.should have_content('baz')

If clicking on the foo link causes triggers an asynchronous process, such as an AJAX request, which, when complete will add the bar link to the page, clicking on the bar link would be expeced to fail, since that link doesn’t exist yet. However Capybara is smart enought to retry finding the link for a brief period of time before giving up and throwing an error. The same is true of the next line, which looks for the content baz on the page; it will retry looking for that content for a brief time. You can adjust how long this period is (the default is 2 seconds):

Capybara.default_wait_time = 5

Be aware that because of this behaviour, the following two statements are not equivalent, and you should always use the latter!

page.should_not have_xpath('//a')
page.should have_no_xpath('//a')

The former would incorrectly wait for the content to appear, since the asynchronous process has not yet removed the element from the page, it would therefore fail, even though the code might be working correctly. The latter correctly waits for the element to disappear from the page.

Using the DSL outside cucumber

You can mix the DSL into any context, for example you could use it in RSpec examples. Just load the DSL and include it anywhere:

require 'capybara'
require 'capybara/dsl'

Capybara.default_driver = :culerity

module MyModule
  include Capybara

  def login!
    within("//form[@id='session']") do
      fill_in 'Login', :with => '[email protected]'
      fill_in 'Password', :with => 'password'
    end
    click_link 'Sign in'
  end
end

Calling remote servers

Normally Capybara expects to be testing an in-process Rack application, but you can also use it to talk to a web server running anywhere on the internets, by setting app_host:

Capybara.current_driver = :selenium
Capybara.app_host = 'http://www.google.com'
... 
visit('/')

Note that rack-test does not support running against a remote server. With drivers that support it, you can also visit any URL directly:

visit('http://www.google.com')

By default Capybara will try to boot a rack application automatically. You might want to switch off Capybara’s rack server if you are running against a remote application:

Capybara.run_server = false

Using the sessions manually

For ultimate control, you can instantiate and use a session manually.

require 'capybara'

session = Capybara::Session.new(:culerity, my_rack_app)
session.within("//form[@id='session']") do
  session.fill_in 'Login', :with => '[email protected]'
  session.fill_in 'Password', :with => 'password'
end
session.click_link 'Sign in'

XPath and CSS

Capybara does not try to guess what kind of selector you are going to give it, if you want to use XPath with your ‘within’ declarations for example, you’ll need to do:

within(:xpath, '//ul/li') { ... }
find(:xpath, '//ul/li').text
find(:xpath, '//li[contains(.//a[@href = "#"]/text(), "foo")]').value

Alternatively you can set the default selector to XPath:

Capybara.default_selector = :xpath
find('//ul/li').text

Beware the XPath // trap

In XPath the expression // means something very specific, and it might not be what you think. Contrary to common belief, // means “anywhere in the document” not “anywhere in the current context”. As an example:

page.find('//body').all('//script')

You might expect this to find all script tags in the body, but actually, it finds all script tags in the entire document, not only those in the body! What you’re looking for is the .// expression which means “any descendant of the current node”:

page.find('//body').all('.//script')

The same thing goes for within:

within('//body') do
  page.find('.//script')
end

Gotchas:

Access to session and request is not possible from the test, Access to response is limited. Some drivers allow access to response headers and HTTP status code, but this kind of functionality is not provided by some drivers, such as Selenium.
Access to Rails specific stuff (such as controller) is unavailable, since we’re not using Rails’ integration testing.
Freezing time: It’s common practice to mock out the Time so that features that depend on the current Date work as expected. This can be problematic, since Capybara’s AJAX timing uses the system time, resulting in Capybara never timing out and just hanging when a failure occurs. It’s still possible to use plugins which allow you to travel in time, rather than freeze time. One such plugin is Timecop.

License:

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the ‘Software’), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ‘AS IS’, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.