To install Cukable, simply do:

$ gem install cukable


FitNesse uses a JSON format for its test reporting, so you must enable the SLIM JSON output formatter provided by Cukable. To make Cucumber aware of this formatter, add this line:

require 'cukable/slim_json_formatter'

to your features/support/env.rb, features/support/custom_env.rb, or wherever you're keeping custom initialization for your Cucumber environment.

Next: Converting Existing Features