dm-2 heckle spec style helper

foo.rb

class Foo
  def bar
    :baz
  end
end

spec_unit_foo_bar_spec.rb

# Spec in directory spec/unit/foo/bar_spec.rb

# Automagically specs Foo#bar !

unit_spec do
  object_args { [] } # also empty per default 
  method_args { [] } # alos empty per default

  # No need to define subject!

  context do
    idempoten_method # acts like it_should_behave_like 'an idempotent method'
    #command_method   # acts like it_should_behave_like 'a command method'

    it 'should something' do
      should be(:bar)
    end
  end
end

unit_spec_helper.rb

module Kernel
  def unit_spec(&block)
    file = caller(1).first.split(':').first
    parts = file.split("/spec/unit/").last.split('/')
    match = parts.last.match(/\A(.*)_spec.rb\Z/)
    match || raise
    parts = parts[0..-2]
    singleton = false
    if %w(singleton_methods class_methods).include?(parts.last)
      parts = parts[0..-2]
      singleton = true
    end
    constant = parts.map { |name| name.capitalize }.inject(Object) do |constant, name|
      name = name.split('_').map(&:capitalize).join('')
      constant.const_get(name)
    end

    delim = singleton ? '.' : '#'
    method_name = match[1]
    describe constant, "#{delim}#{method_name}" do
      def self.method_args(&block)
        let(:method_args, &block)
      end

      def self.attributes(&block)
        let(:attributes, &block)
        object_args { [attributes] }
      end

      def self.object_args(&block)
        let(:object_args, &block)
      end

      def self.object(&block)
        let(:object, &block)
      end

      def self.command_method
        it_should_behave_like 'a command method'
      end

      def self.idempotent_method
        it_should_behave_like 'an idempotent method'
      end

      if singleton
        object { described_class }
      else
        object_args { [] }
        object      { described_class.new(*object_args) }
      end

      method_args { [] }
      subject { object.public_send(method_name, *method_args) }

      class_eval(&block)
    end
  end
end