[![Build Status](https://travis-ci.org/donv/capybara-screenshot-diff.svg?branch=master)](https://travis-ci.org/donv/capybara-screenshot-diff) # Capybara::Screenshot::Diff Ever wondered what your project looked like two years ago? To answer that, you start taking screen shots during your tests. Capybara provides the `save_screenshot` method for this. Very good. Ever introduced a graphical change unintended? Never want it to happen again? Then this gem is for you! Use this gem to detect changes in your pages by taking screen shots and comparing them to the previous revision. ## Installation Add this line to your application's Gemfile: ```ruby gem 'capybara-screenshot-diff' ``` And then execute: $ bundle Or install it yourself as: $ gem install capybara-screenshot-diff ## Usage Add `screenshot ''` to your tests. The screenshot will be saved in the `doc/screenshots` directory. Change your existing `save_screenshot` calls to `screenshot` ```ruby test 'my useful feature' do visit '/' screenshot 'welcome_index' click_button 'Useful feature' screenshot 'feature_index' click_button 'Perform action' screenshot 'action_performed' end ``` This will produce a sequence of images like this ``` doc screenshots action_performed feature_index welcome_index ``` To store the screen shot history, add the `doc/screenshots` directory to your version control system (git, svn, etc). ### Screenshot groups Commonly it is useful to group screenshots around a feature, and record them as a sequence. To do this, add a `screenshot_group` call to the start of your test. ```ruby test 'my useful feature' do screenshot_group 'useful_feature' visit '/' screenshot 'welcome_index' click_button 'Useful feature' screenshot 'feature_index' click_button 'Perform action' screenshot 'action_performed' end ``` This will produce a sequence of images like this ``` doc screenshots useful_feature 00-welcome_index 01-feature_index 02-action_performed ``` **All files in the screenshot group directory will be deleted when `screenshot_group` is called.** #### Screenshot sections You can introduce another level above the screenshot group called a `screenshot_section`. The section name is inserted just before the group name in the save path. If called in the setup of the test, all screenshots in that test will get the same prefix: ```ruby setup do screenshot_section 'my_feature' end test 'my subfeature' do screenshot_group 'subfeature' visit '/feature' click_button 'Interresting button' screenshot 'subfeature_index' click_button 'Perform action' screenshot 'action_performed' end ``` This will produce a sequence of images like this ``` doc screenshots my_feature subfeature 00-subfeature_index 01-action_performed ``` ### Multiple Capybara drivers Often it is useful to test your app using different browsers. To avoid the screenshots for different Capybara drivers to overwrite each other, set ```ruby Capybara::Screenshot.add_driver_path = true ``` The example above will then save your screenshots like this (for poltergeist and selenium): ``` doc screenshots poltergeist useful_feature 00-welcome_index 01-feature_index 02-action_performed selenium useful_feature 00-welcome_index 01-feature_index 02-action_performed ``` ### Multiple OSs If you run your tests on multiple operating systems, you will most likely find the screen shots differ. To avoid the screenshots for different OSs to overwrite each other, set ```ruby Capybara::Screenshot.add_os_path = true ``` The example above will then save your screenshots like this (for Linux and Windows): ``` doc screenshots linux useful_feature 00-welcome_index 01-feature_index 02-action_performed windows useful_feature 00-welcome_index 01-feature_index 02-action_performed ``` If you combine this config with the `add_driver_path` config, the driver will be put in front of the OS name. ### Screen size You can specify the desired screen size using ```ruby Capybara::Screenshot.window_size = [1024, 768] ``` This will force the screen shots to the given size, and skip taking screen shots unless the desired window size can be achieved. ### Disabling screen shots If you want to skip taking screen shots, set ```ruby Capybara::Screenshot.enabled = false ``` You can of course set this by an environment variable ```ruby Capybara::Screenshot.enabled = ENV['TAKE_SCREENSHOTS'] ``` ### Disabling diff If you want to skip the assertion for change in the screen shot, set ```ruby Capybara::Screenshot::Diff.enabled = false ``` Using an environment variable ```ruby Capybara::Screenshot::Diff.enabled = ENV['COMPARE_SCREENSHOTS'] ``` ### Screen shot save path If you would like the screen shots to be saved in a different location set ```ruby Capybara::Screenshot.save_path = "#{Rails.root}/doc/gui" ``` ### Screen shot stability To ensure that animations are finished before saving a screen shot, you can add a stability time limit. If the stability time limit is set, a second screen shot will be taken and compared to the first. This is repeated until two subsequent screen shots are identical. ```ruby Capybara::Screenshot.stability_time_limit = 0.5 ``` ## Development After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment. To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `lib/capybara/screenshot/diff/version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org). ## Contributing Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/capybara-screenshot-diff. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct. ## License The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).