capybara-screenshot gem

Capture a screen shot for every test failure automatically!

capybara-screenshot used with Capybara and Cucumber, Rspec or Minitest, will capture a screen shot for each failure in your test suite. The HTML for the failed page, and a screenshot image (when using capybara-webkit, Selenium or poltergeist) is saved into $APPLICATION_ROOT/tmp/capybara.

Having screenshots readily available for each test failure is incredibly helpful when trying to quickly diagnose a problem in your failing steps. You can view the source code, and have a screen shot of the page (when applicable), at the time of each failure.

Please note that Ruby 1.9+ is required to use this Gem. For Ruby 1.8 support, please see the capybara-screenshot Ruby 1.8 branch

Installation

Step 1: install the gem

Using Bundler, add the following to your Gemfile

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

or install manually using Ruby Gems:

gem install capybara-screenshot

Step 2: load capybara-screenshot into your tests

Cucumber

In env.rb or a support file, please add:

require 'capybara-screenshot/cucumber'

RSpec

In rails_helper.rb, spec_helper.rb, or a support file, after the require for 'capybara/rspec', please add:

# remember: you must require 'capybara/rspec' first
require 'capybara-screenshot/rspec'

Note: As of RSpec Rails 3.0, it is recommended that all your Rails environment code is loaded into rails_helper.rb instead of spec_helper.rb, and as such, the capybara-screenshot require should be located in rails_helper.rb. See the RSpec Rails 3.0 upgrade notes for more info.

Minitest

Typically in 'test/test_helper.rb', please add:

require 'capybara-screenshot/minitest'

Test::Unit

Typically in 'test/test_helper.rb', please add:

require 'capybara-screenshot/testunit'

By default, screenshots will be captured for Test::Unit tests in the path 'test/integration'. You can add additional paths as:

Capybara::Screenshot.testunit_paths << 'test/feature'

Manual screenshots

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

Driver configuration

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.

Capybara-webkit defaults to a screenshot size of 1000px by 10px. To specify a custom size, use the following option:

Capybara::Screenshot.webkit_options = { width: 1024, height: 768 }

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 your driver is based on existing browser driver, like Firefox, instead of .super_dooper_render do driver.browser.save_screenshot path.

Custom screenshot filename

If you want to control the screenshot filename for a specific test library, 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(' ', '-').gsub(/^.*\/spec\//,'')}"
end

By default capybara-screenshot will append a timestamp to the basename. If you want to disable this behavior set the following option:

Capybara::Screenshot.append_timestamp = false

Custom screenshot directory

By default screenshots are saved into $APPLICATION_ROOT/tmp/capybara. If you want to customize the location, override the file path as:

Capybara.save_and_open_page_path = "/file/path"

Pruning old screenshots automatically

By default screenshots are saved indefinitely, if you want them to be automatically pruned on a new failure, then you can specify one of the following prune strategies as follows:

# Keep only the screenshots generated from the last failing test suite
Capybara::Screenshot.prune_strategy = :keep_last_run

# Keep up to the number of screenshots specified in the hash
Capybara::Screenshot.prune_strategy = { keep: 20 }

Information about screenshots in RSpec output

By default, capybara-screenshot extend RSpec’s formatters to include a link to the screenshot and/or saved html page for each failed spec. If you want to disable this feature completely (eg. to avoid problems with CI tools), use:

Capybara::Screenshot::RSpec.add_link_to_screenshot_for_failed_examples = false

It’s also possible to directly embed the screenshot image in the output if you’re using RSpec’s HtmlFormatter:

Capybara::Screenshot::RSpec::REPORTERS["RSpec::Core::Formatters::HtmlFormatter"] = Capybara::Screenshot::RSpec::HtmlEmbedReporter

If you want to further customize the information added to RSpec’s output, just implement your own reporter class and customize Capybara::Screenshot::RSpec::REPORTERS accordingly. See rspec.rb for more info.

Common problems

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.

Also make sure that you're not calling Capybara.reset_sessions! before the screenshot hook runs. For RSpec you want to make sure that you're using append_after instead of after, for instance:

config.append_after(:each) do
  Capybara.reset_sessions!
end

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

Repository & Contributing to this Gem

Bugs

Please raise an issue at https://github.com/mattheworiordan/capybara-screenshot/issues and ensure you provide sufficient detail to replicate the problem.

Contributions

Contributions are welcome. Please fork this gem, and submit a pull request. New features must include test coverage and must pass on all versions of the testing frameworks supported. Run appraisal "bundle exec rspec && bundle exec cucumber" locally to test your changes against all versions of testing framework gems supported.

Rubygems

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

About

This gem was written by Matthew O'Riordan, with contributions from many kind people.