Using this gem, whenever a Capybara test in Cucumber, Rspec or Minitest fails, the HTML for the failed page and a screenshot (when using capybara-webkit, Selenium or poltergeist) is saved into $APPLICATION_ROOT/tmp/capybara.

This is a huge help when trying to diagnose a problem in your failing steps as you can view the source code and potentially how the page looked at the time of the failure.

Using Bundler, add the following to your Gemfile

gem 'capybara-screenshot', :group => :test

or install manually using Ruby Gems:

gem install capybara-screenshot

For Cucumber, in env.rb or a support file, please add:

require 'capybara-screenshot/cucumber'

For RSpec, in spec_helper.rb or a support file, after the require for 'capybara/rspec', please add:

# you should require 'capybara/rspec' first
require 'capybara-screenshot/rspec'

For Minitest, typically in 'test/test_helper.rb', please add:

require 'capybara-screenshot/minitest'

If you require more control, you can generate the screenshot on demand rather than on failure. This is useful if the failure occurs at a point where the screen shot is not as useful for debugging a rendering problem. This can be more useful if you disable the auto-generate on failure feature with the following config

Capybara::Screenshot.autosave_on_failure = false

Anywhere the Capybara DSL methods (visit, click etc.) are available so too are the screenshot methods.

screenshot_and_save_page

Or for screenshot only, which will automatically open the image.

screenshot_and_open_image

These are just calls on the main library methods.

Capybara::Screenshot.screenshot_and_save_page
Capybara::Screenshot.screenshot_and_open_image

The gem supports the default rendering method for Capybara to generate the screenshot, which is:

page.driver.render(path)

There are also some specific driver configurations for Selenium, Webkit, and Poltergeist. See the definitions here. The Rack::Test driver, Rails' default, does not allow rendering, so it has a driver definition as a noop.

If a driver is not found the default rendering will be used. If this doesn't work with your driver, then you can add another driver configuration like so

# The driver name should match the Capybara driver config name.
Capybara::Screenshot.register_driver(:exotic_browser_driver) do |driver, path|
  driver.super_dooper_render(path)
end

If you want to control the screenshot filename for a specific test libarary, to inject the test name into it for example, you can override how the basename is generated for the file like so

Capybara::Screenshot.register_filename_prefix_formatter(:rspec) do |example|
    "screenshot-#{example.description.gsub(' ', '-')}"
  end
end

By default capybara-screenshot will append the screenshot path to a failing spec's full_description which effectively changes the name of the spec and breaks trend reporting using tools like CI Reporter. You can turn off the default behavior with the following invocation

Capybara::Screenshot.append_screenshot_path = false

A simple Rails 3.1 example application has been set up at https://github.com/mattheworiordan/capybara-screenshot-test-rails-3.1 Git clone the app, and then run Cucumber rake cucumber, RSpec rake spec and Minitest rake test and expect intentional failures. Now check the $APPLICATION_ROOT/tmp/capybara folder for the automatic screen shots generated from failed tests.

If you have recently upgraded from v0.2, or you find that screen shots are not automatically being generated, then it's most likely you have not included the necessary require statement for your testing framework described above. As of version 0.3, without the explicit require, Capybara-Screenshot will not automatically take screen shots. Please re-read the installation instructions above.

Raise an issue on the Capybara-Screenshot issue tracker if you are still having problems.

Please fork, submit patches or feedback at https://github.com/mattheworiordan/capybara-screenshot

The gem details on RubyGems.org can be found at https://rubygems.org/gems/capybara-screenshot

This gem was written by Matthew O'Riordan

• http://mattheworiordan.com
• @mattheworiordan
• Linked In

Copyright © 2012 Matthew O'Riordan, inc. It is free software, and may be redistributed under the terms specified in the LICENSE file.