Record videos of your UI based (Selenium) automated tests

My latest project, screen-recorder, is a Ruby gem that allows you to record your desktop or a specific application window. The gem is primarily geared towards browser based automated tests using Selenium, Watir, or Capybara. However, any Ruby based project should be able to use it. It works on Windows, Linux, and macOS.

If you are familiar with SauceLabs or BrowserStack, you may be aware of their video recording feature. In addition to providing screenshots and a log, these services provide an option to record the test execution which could help you easily debug those UI tests failures. You are able to see the test execution in action and see what happened before, during, and after a test failure or an application stack trace. This aids in debugging and documenting test cases or application bugs.

However, if you are not using these services and are interested in recording your test executions, check out the gem on GitHub. Here is a quick overview of the features:

Record your desktop

This mode records the whole screen and is best suited if your tests launch multiple windows or if they resize the browser/GUI during the execution.

@recorder = 'recording.mkv')

# Run tests or whatever you want to record


Record a specific window (Microsoft Windows only)

This mode records a specific application window with the given window title. This keeps the focus limited to your application and keeps the recording size relatively smaller than the desktop mode, unless of course you maximize the window and record fullscreen.

require 'watir'

browser   = :firefox
@recorder = 'Mozilla Firefox', output: 'recording.mkv')

# Run tests or whatever you want to record


Fetch Window Title

A helper method is available to fetch the title of the active window for the given process name.

ScreenRecorder::Window.fetch_title('firefox') # Name of exe
#=> ["Mozilla Firefox"]

#=> ["New Tab - Google Chrome"]

This mode has limited capabilities. Read more about it in the wiki here.


Once the recorder is stopped, you can view the video metadata or transcode it if desired.
=> #<FFMPEG::Movie:0x0000000004327900 
        @metadata={:streams=>[{:index=>0, :codec_name=>"h264", :codec_long_name=>"H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10", 
        ... >"movie.mp4") { |progress| puts progress } # 0.2 ... 0.5 ... 1.0

Discard Recoding

If your test execution passes, you can easily discard the recording through @recorder.discard or @recorder.delete.

Advanced Options

You can provide additional parameters to FFmpeg using the advanced parameter. You can specify input/output specific parameters using the input: {} and output: {} within the advanced Hash.

advanced = {
  input:    {
    framerate:  30,
    pix_fmt:    'yuv420p',
    video_size: '1280x720'
  output:   {
    r:       15, # Framerate
    pix_fmt: 'yuv420p'
  log:      'recorder.log',
  loglevel: 'level+debug', # For FFmpeg
} 'recording.mkv', advanced: advanced)

This will be parsed as:

ffmpeg -y -f gdigrab -framerate 30 -pix_fmt yuv420p -video_size 1280x720 -i desktop -r 15 pix_fmt yuv420p -loglevel level+debug recording.mkv

Use with Cucumber

A Cucumber + Watir based example is available here.

More Information

A list of planned features and bugs can be found on the Issues page.

Thank you for reading!

Written on January 20, 2019