teamcapybara--capybara/README.rdoc

= Capybara

Capybara helps you test Rails and Rack applications by simulating how a real
user would interact with your app. It is agnostic about the driver running your
tests and comes with Rack::Test and Selenium support built in. WebKit is
supported through an external gem.

<b>Need help?</b> Ask on the mailing list (please do not open an issue on
GitHub): http://groups.google.com/group/ruby-capybara

== Setup

To install, type

    sudo gem install capybara

If you are using Rails, add this line to your test helper file:

    require 'capybara/rails'

If you are not using Rails, set Capybara.app to your rack app:

    Capybara.app = MyRackApp

== Using Capybara with Cucumber

The <tt>cucumber-rails</tt> gem comes with Capybara support built-in. If you
are not using Rails, manually load the <tt>capybara/cucumber</tt> module:

    require 'capybara/cucumber'
    Capybara.app = MyRackApp

You can use the Capybara DSL in your steps, like so:

    When /I sign in/ do
      within("#session") do
        fill_in 'Login', :with => 'user@example.com'
        fill_in 'Password', :with => 'password'
      end
      click_link 'Sign in'
    end

You can switch to the <tt>Capybara.javascript_driver</tt> (<tt>:selenium</tt>
by default) by tagging scenarios (or features) with <tt>@javascript</tt>:

    @javascript
    Scenario: do something Ajaxy
      When I click the Ajax link
      ...

There are also explicit <tt>@selenium</tt> and <tt>@rack_test</tt>
tags set up for you.

== Using Capybara with RSpec

Load RSpec 2.x support by adding the following line (typically to your
<tt>spec_helper.rb</tt> file):

    require 'capybara/rspec'

If you are using Rails, put your Capybara specs in <tt>spec/requests</tt> or
<tt>spec/integration</tt>.

If you are not using Rails, tag all the example groups in which you want to use
Capybara with <tt>:type => :request</tt>.

You can now write your specs like so:

    describe "the signup process", :type => :request do
      before :each do
        User.make(:email => 'user@example.com', :password => 'caplin')
      end

      it "signs me in" do
        within("#session") do
          fill_in 'Login', :with => 'user@example.com'
          fill_in 'Password', :with => 'password'
        end
        click_link 'Sign in'
      end
    end

Use <tt>:js => true</tt> to switch to the <tt>Capybara.javascript_driver</tt>
(<tt>:selenium</tt> by default), or provide a <tt>:driver</tt> option to switch
to one specific driver. For example:

    describe 'some stuff which requires js', :js => true do
      it 'will use the default js driver'
      it 'will switch to one specific driver', :driver => :webkit
    end

Finally, Capybara also comes with a built in DSL for creating descriptive acceptance tests:

    feature "Signing up" do
      background do
        User.make(:email => 'user@example.com', :password => 'caplin')
      end

      scenario "Signing in with correct credentials" do
        within("#session") do
          fill_in 'Login', :with => 'user@example.com'
          fill_in 'Password', :with => 'caplin'
        end
        click_link 'Sign in'
      end
    end

<tt>feature</tt> is in fact just an alias for <tt>describe ..., :type =>
:request</tt>, <tt>background</tt> is an alias for <tt>before</tt>, and
<tt>scenario</tt> for <tt>it</tt>.

== Using Capybara with Test::Unit

* If you are using Rails, add <tt>database_cleaner</tt> to your Gemfile:

      group :test do
        gem 'database_cleaner'
      end

  Then add the following code in your <tt>test_helper.rb</tt> file to make
  Capybara available in all test cases deriving from
  <tt>ActionDispatch::IntegrationTest</tt>:

      # Transactional fixtures do not work with Selenium tests, because Capybara
      # uses a separate server thread, which the transactions would be hidden
      # from. We hence use DatabaseCleaner to truncate our test database.
      DatabaseCleaner.strategy = :truncation

      class ActionDispatch::IntegrationTest
        # Make the Capybara DSL available in all integration tests
        include Capybara::DSL

        # Stop ActiveRecord from wrapping tests in transactions
        self.use_transactional_fixtures = false

        teardown do
          # Truncate the database
          DatabaseCleaner.clean
          # Forget the (simulated) browser state
          Capybara.reset_sessions!
          # Revert Capybara.current_driver to Capybara.default_driver
          Capybara.use_default_driver
        end
      end

* If you are not using Rails, define a base class for your Capybara tests like
  so:

      class CapybaraTestCase < Test::Unit::TestCase
        include Capybara::DSL

        def teardown
          Capybara.reset_sessions!
          Capybara.use_default_driver
        end
      end

  Remember to call <tt>super</tt> in any subclasses that override
  <tt>teardown</tt>.

To switch the driver, set <tt>Capybara.current_driver</tt>. For instance,

    class BlogTest < ActionDispatch::IntegrationTest
      setup do
        Capybara.current_driver = Capybara.javascript_driver # :selenium by default
      end

      test 'shows blog posts'
        # ... this test is run with Selenium ...
      end
    end

== Using Capybara with MiniTest::Spec

Set up your base class as with Test::Unit. (On Rails, the right base class
could be something other than ActionDispatch::IntegrationTest.)

The capybara_minitest_spec gem ({Github}[https://github.com/ordinaryzelig/capybara_minitest_spec],
{rubygems.org}[https://rubygems.org/gems/capybara_minitest_spec]) provides MiniTest::Spec
expectations for Capybara. For example:

    page.must_have_content('Important!')

== Drivers

Capybara uses the same DSL to drive a variety of browser and headless drivers.

=== Selecting the Driver

By default, Capybara uses the <tt>:rack_test</tt> driver, which is fast but does not
support JavaScript.  You can set up a different default driver for your
features. For example if you'd prefer to run everything in Selenium, you could
do:

    Capybara.default_driver = :selenium

However, if you are using RSpec or Cucumber, you may instead want to consider
leaving the faster <tt>:rack_test</tt> as the +default_driver+, and marking only those
tests that require a JavaScript-capable driver using <tt>:js => true</tt> or
<tt>@javascript</tt>, respectively.  By default, JavaScript tests are run using the
<tt>:selenium</tt> driver.  You can change this by setting
<tt>Capybara.javascript_driver</tt>.

You can also change the driver temporarily (typically in the Before/setup and
After/teardown blocks):

    Capybara.current_driver = :webkit  # temporarily select different driver
    ... tests ...
    Capybara.use_default_driver  # switch back to default driver

Note that switching the driver creates a new session, so you may not be able to
switch in the middle of a test.

=== RackTest

RackTest is Capybara's default driver. It is written in pure Ruby and does not
have any support for executing JavaScript. Since the RackTest driver works
directly against the Rack interface, it does not need any server to be started,
it can work directly work against any Rack app. This means that if your
application is not a Rack application (Rails, Sinatra and most other Ruby
frameworks are Rack applications) then you cannot use this driver. You cannot
use the RackTest driver to test a remote application.
{capybara-mechanize}[https://github.com/jeroenvandijk/capybara-mechanize]
intends to provide a similar driver which works against remote servers, it is a
separate project.

RackTest can be configured with a set of headers like this:

    Capybara.register_driver :rack_test do |app|
      Capybara::RackTest::Driver.new(app, :browser => :chrome)
    end

See the section on adding and configuring drivers.

=== Selenium

At the moment, Capybara supports {Selenium 2.0
(Webdriver)}[http://seleniumhq.org/docs/01_introducing_selenium.html#selenium-2-aka-selenium-webdriver],
*not* Selenium RC. Provided Firefox is installed, everything is set up for you,
and you should be able to start using Selenium right away.

Capybara can block and wait for Ajax requests to finish after you've interacted
with the page. To enable this behaviour, set the <tt>:resynchronize</tt> driver
option to <tt>true</tt>. This should normally not be necessary, since
Capybara's automatic reloading should take care of any asynchronicity problems.
See the section on Asynchronous JavaScript for details.

Note: Drivers which run the server in a different thread may not work share the
same transaction as your tests, causing data not to be shared between your test
and test server, see "Transactions and database setup" below.

=== Capybara-webkit

The {capybara-webkit driver}[https://github.com/thoughtbot/capybara-webkit] is for true headless
testing. It uses QtWebKit to start a rendering engine process. It can execute JavaScript as well.
It is significantly faster than drivers like Selenium since it does not load an entire browser.

You can install it with:

  gem install capybara-webkit

And you can use it by:

  Capybara.javascript_driver = :webkit

== The DSL

A complete reference is available at
{at rubydoc.info}[http://rubydoc.info/github/jnicklas/capybara/master].

Note: All searches in Capybara are <b>case sensitive</b>. This is because
Capybara heavily uses XPath, which doesn't support case insensitivity.

=== Navigating

You can use the
<tt>{visit}[http://rubydoc.info/github/jnicklas/capybara/master/Capybara/Session#visit-instance_method]</tt>
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}[http://rubydoc.info/github/jnicklas/capybara/master/Capybara/Session#current_path-instance_method]
of the browsing session for test assertions:

    current_path.should == post_comments_path(post)

=== Clicking links and buttons

<em>Full reference: {Capybara::Node::Actions}[http://rubydoc.info/github/jnicklas/capybara/master/Capybara/Node/Actions]</em>

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_on('Link Text')  # clicks on either links or buttons
    click_on('Button Value')

=== Interacting with forms

<em>Full reference: {Capybara::Node::Actions}[http://rubydoc.info/github/jnicklas/capybara/master/Capybara/Node/Actions]</em>

There are a number of tools for interacting with 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

<em>Full reference: {Capybara::Node::Matchers}[http://rubydoc.info/github/jnicklas/capybara/master/Capybara/Node/Matchers]</em>

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_selector?('table tr')
    page.has_selector?(:xpath, '//table/tr')
    page.has_no_selector?(:content)

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

You can use these with RSpec's magic matchers:

    page.should have_selector('table tr')
    page.should have_selector(:xpath, '//table/tr')
    page.should have_no_selector(:content)

    page.should have_xpath('//table/tr')
    page.should have_css('table tr.foo')
    page.should have_text('foo')
    page.should have_no_text('foo')

Note that there are 2 matchers for checking content/text. <tt>page.has_text?('foo')</tt>
will check only for text that is displayable, whereas <tt>page.has_content?('foo')</tt> will
check for the content within any nodes (including the head section and within script tags).
Most of the time you'll want the behaviour of <tt>page.has_text?('foo')</tt>, so go with that
unless you have a specific reason to use <tt>page.has_content?('foo')</tt> instead.

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

If all else fails, you can also use the
<tt>{page.html}[http://rubydoc.info/github/jnicklas/capybara/master/Capybara/Session#html-instance_method]</tt>
method to test against the raw HTML:

    page.html.should match /<span>.../i

=== Finding

<em>Full reference: {Capybara::Node::Finders}[http://rubydoc.info/github/jnicklas/capybara/master/Capybara/Node/Finders]</em>

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 <tt>find</tt> 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
<tt>{within}[http://rubydoc.info/github/jnicklas/capybara/master/Capybara/Session#within-instance_method]</tt>
method. Optionally you can specify which kind of selector to use.

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

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

Note that <tt>within</tt> will scope the actions to the _first_ (not _any_)
element that matches the 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

== Transactions and database setup

Some Capybara drivers need to run against an actual HTTP server. Capybara takes
care of this and starts one for you in the same process as your test, but on
another thread. Selenium is one of those drivers, whereas RackTest is not.

If you are using an SQL database, it is common to run every test in a
transaction, which is rolled back at the end of the test, rspec-rails does this
by default out of the box for example. Since transactions are usually not
shared across threads, this will cause data you have put into the database in
your test code to be invisible to Capybara.

Cucumber handles this by using truncation instead of transactions, i.e. they
empty out the entire database after each test. You can get the same behaviour
by using a gem such as {database_cleaner}[https://github.com/bmabey/database_cleaner].

It is also possible to force your ORM to use the same transaction for all
threads.  This may have thread safety implications and could cause strange
failures, so use caution with this approach. It can be implemented in
ActiveRecord through the following monkey patch:

    class ActiveRecord::Base
      mattr_accessor :shared_connection
      @@shared_connection = nil

      def self.connection
        @@shared_connection || retrieve_connection
      end
    end
    ActiveRecord::Base.shared_connection = ActiveRecord::Base.connection

== 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_text('baz')

If clicking on the *foo* link 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 expected 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.has_xpath?('a')
    page.has_no_xpath?('a')

The former would immediately fail because the content has not yet been removed.
Only the latter would wait for the asynchronous process to remove the content
from the page.

Capybara's Rspec matchers, however, are smart enough to handle either form.
The two following statements are functionally equivalent:

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

Capybara's waiting behaviour is quite advanced, and can deal with situations
such as the following line of code:

    find('#sidebar').find('h1').should have_text('Something')

Even if JavaScript causes <tt>#sidebar</tt> to disappear off the page, Capybara
will automatically reload it and any elements it contains. So if an AJAX
request causes the contents of <tt>#sidebar</tt> to change, which would update
the text of the <tt>h1</tt> to "Something", and this happened, this test would
pass. If you do not want this behaviour, you can set
<tt>Capybara.automatic_reload</tt> to <tt>false</tt>.

== Using the DSL in unsupported testing frameworks

You can mix the DSL into any context by including <tt>Capybara::DSL</tt>:

    require 'capybara'
    require 'capybara/dsl'

    Capybara.default_driver = :webkit

    module MyModule
      include Capybara::DSL

      def login!
        within("//form[@id='session']") do
          fill_in 'Login', :with => 'user@example.com'
          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 the default driver (<tt>:rack_test</tt>) 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}[http://rubydoc.info/github/jnicklas/capybara/master/Capybara/Session]
manually.

    require 'capybara'

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

== XPath, CSS and selectors

Capybara does not try to guess what kind of selector you are going to give it,
and will always use CSS by default.  If you want to use XPath, 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

Capybara allows you to add custom selectors, which can be very useful if you
find yourself using the same kinds of selectors very often:

    Capybara.add_selector(:id) do
      xpath { |id| XPath.descendant[XPath.attr(:id) == id.to_s] }
    end

    Capybara.add_selector(:row) do
      xpath { |num| ".//tbody/tr[#{num}]" }
    end

    Capybara.add_selector(:flash_type) do
      css { |type| "#flash.#{type}" }
    end

The block given to xpath must always return an XPath expression as a String, or
an XPath expression generated through the XPath gem. You can now use these
selectors like this:

    find(:id, 'post_123')
    find(:row, 3)
    find(:flash_type, :notice)

You can specify an optional match option which will automatically use the
selector if it matches the argument:

    Capybara.add_selector(:id) do
      xpath { |id| XPath.descendant[XPath.attr(:id) == id.to_s] }
      match { |value| value.is_a?(Symbol) }
    end

Now use it like this:

    find(:post_123)

This :id selector is already built into Capybara by default, so you don't
need to add it yourself.

== 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(:xpath, '//body').all(:xpath, '//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(:xpath, '//body').all(:xpath, './/script')

The same thing goes for within:

    within(:xpath, '//body') do
      page.find(:xpath, './/script')
      within(:xpath, './/table/tbody') do
        ...
      end
    end

== Configuring and adding drivers

Capybara makes it convenient to switch between different drivers. It also exposes
an API to tweak those drivers with whatever settings you want, or to add your own
drivers. This is how to switch the selenium driver to use chrome:

    Capybara.register_driver :selenium do |app|
      Capybara::Selenium::Driver.new(app, :browser => :chrome)
    end

However, it's also possible to give this a different name, so tests can switch
between using different browsers effortlessly:

    Capybara.register_driver :selenium_chrome do |app|
      Capybara::Selenium::Driver.new(app, :browser => :chrome)
    end

Whatever is returned from the block should conform to the API described by
Capybara::Driver::Base, it does not however have to inherit from this class.
Gems can use this API to add their own drivers to Capybara.

The {Selenium wiki}[http://code.google.com/p/selenium/wiki/RubyBindings] has
additional info about how the underlying driver can be configured.

== 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 <tt>controller</tt>) 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}[http://github.com/jtrupiano/timecop].

* When using Rack::Test, beware if attempting to visit absolute URLs. For
  example, a session might not be shared between visits to <tt>posts_path</tt>
  and <tt>posts_url</tt>. If testing an absolute URL in an Action Mailer email,
  set <tt>default_url_options</tt> to match the Rails default of
  <tt>www.example.com</tt>.

== Development

If you found a _reproducible_ bug, open a {GitHub
Issue}[http://github.com/jnicklas/capybara/issues] to submit a bug report.

Even better, send a pull request! Make sure all changes are well tested,
Capybara is a testing tool after all. Topic branches are good.

To set up a development environment, simply do:

    git submodule update --init
    gem install bundler
    bundle install