Rspec - Inheritance matcher

inherit_from_matcher.rb

RSpec::Matchers.define :inherit_from do |superclass|
  match do |klass|
    klass.class.ancestors.include? superclass
  end

  failure_message_for_should do |klass|
    "expected #{klass.class.name} to inherit from #{superclass}"
  end

  failure_message_for_should_not do |klass|
    "expected #{klass.class.name} not to inherit from #{superclass}"
  end

end