Cases

class TestResponse
  attr_reader :options

  def initialize(options)
    @options = options
  end

  def failed?
    options[:failed]
  end

  def failed_message
    "failed message from test response"
  end

  def success?
    options[:success]
  end

  def success_message
    "success message from test response"
  end
end

class TestCases
  include Cases

  attr_reader :response

  def initialize(response)
    @response = response
  end

  def failed_message
    "failed message from cased object"
  end

  def success_message
    "success message from cased object"
  end

  def test_with_block
    response
  end
  define_case(:test_with_block, :success?) { |response| response.success_message }
  define_case(:test_with_block, :failed?) { |response| response.failed_message }

  def test_without_block
    response
  end
  define_case(:test_without_block, success?: :success_message)
  define_case(:test_without_block, failed?: :failed_message)

  def test_caseable
    response
  end
  define_caseable(:test_caseable)
end

> # When the test response was a success
> test_response = TestResponse.new(success: true, failed: false)
> test_case = TestCases.new(test_response)
> test_case.test_with_block
 => "success message from test response"
> test_case.test_without_block
 => "success message from cased object"
> test_case.test_caseable do |on|
    on.success? { |response| "#{response.success_message} through caseable" }
    on.failed? { |response| "#{response.failed_message} through caseable" }
  end
 => "success message from test response through caseable"
>
> # When the test response failed
> test_response = TestResponse.new(success: false, failed: true)
> test_case = TestCases.new(test_response)
> test_case.test_with_block
 => "failed message from test response"
> test_case.test_without_block
 => "failed message from cased object"
> test_case.test_caseable do |on|
    on.success? { |response| "#{response.success_message} through caseable" }
    on.failed? { |response| "#{response.failed_message} through caseable" }
  end
 => "failed message from test response through caseable"