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Automated visual testing of Android/iOS applications.

Nakal is used to add visual validations in your existing test framework (using appium or calabash etc).


You need to install imagemagick on your machine

Add this line to your application's Gemfile:

gem 'nakal'

And then execute:

$ bundle

Or install it yourself as:

$ gem install nakal


If you are using cucumber, include following Lines in your env.rb

require "nakal/cucumber"
Nakal.platform = :android

for ios, set:

Nakal.platform = :ios

and then put this line in your automation code, at all places where a new screen loads:

diff_metric = nakal_execute("current_screen_name")

Now, execute your test by passing env variable NAKAL_MODE=build to build the baseline images. All baseline images will be stored in baseline_images folder in current directory

once baseline is built, next execution onwards, start using environment variable NAKAL_MODE=compare to compare against baseline. any difference will be put in the same directory with image file named "current_screen_name_diff.png"

If You want to organize baseline nicely, you can even specify sub-paths in #nakal_execute like this:

diff_metric = nakal_execute("feature/sub_feature/current_screen_name")

For setting custom directory, use: "<desired_directory>"
Nakal.device_name = "nexus7"

For cropping the notification bar OR scroll bar, create a config/nakal.yml file in execution directory.


put these contents in your nakal.yml file inside config/nakal.yml

 top: 50
 right: 18
 left: 0
 bottom: 0
 screen_name_to_be_masked: {mask_region: [66,424,340,478]}
 feature/sub_feature/current_screen_name: {mask_region_1: [66,424,340,478],mask_region_2: [76,524,440,578]}

 top: 74
 right: 20
 left: 0
 bottom: 0

 top: 30
 right: 6
 left: 0
 bottom: 0
 screen_name_to_be_masked: {mask_region: [66,424,340,478]}
 feature/sub_feature/current_screen_name: {mask_region_1: [66,424,340,478],mask_region_2: [76,524,440,578]}


  1. There is implicit wait of 30 sec until current screen matches baseline. This timeout can be changed by setting:

    Nakal.timeout = new_timeout_value
  2. you can specify the areas of a screen you want to mask/ignore while comparing in nakal.yml as below:

     top: 50
     right: 18
     left: 0
     bottom: 0
     screen_name_to_be_masked: {mask_region_1: [66,424,340,478],mask_region_2: [76,524,440,578]}
  3. If you want to set certain threshold while comparing. You can pass option as:

    diff_metric = nakal_execute("current_screen_name",{:acceptable_diff => "#{your_acceptable_diff_metric}".to_f})


  1. Fork it ( )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request