Inheritance

FakerMaker can exploit the Ruby class hierarchy to provide additional specialisation or to override some behaviours:

FakerMaker.factory :vehicle do
  wheels { 4 }
  colour { Faker::Color.color_name }
  engine_capacity { rand( 600..2500 ) }
end

FakerMaker.factory :motorbike, parent: :vehicle do
  wheels { 2 }
  sidecar { [true, false].sample }
end

This is the equivalent of:

class Vehicle < Object
  # ...
end

class Motorbike < Vehicle
  # ...
end

so a motorbike will still have a colour and engine capacity between 600 and 2500.