Question

In rpsec 2.12 I expected this helper method definition to work:

module X
private
  def build_them(type)
    puts 'Catching the star'
  end  
end
context 'public/private instance methods' do
  subject{ Class.new { extend(::X) } }
  def subject.build(type)
    puts "Throwing a star"
    build_them(type)
  end
  it{ should respond_to :build}
end

The actual result is a failed spec:

expected #<Class:0x00000002ea5f90> to respond to :build

I expected the example to pass

Any suggestions on how to do this correctly?

Answer 1

Calling subject without passsing a block actually returns the ‘subject’ block in proc form. This means that in your code, when you do this:

def subject.build(type)
  #...
end

You are actually defining ‘build’ on the proc itself, not the object that the proc returns.

In the it {...} example block, the expectations are executed against the object that the proc returns, so the test fails as you’ve seen.

To make the test pass, you would need to define the ‘build’ method on the actual object that the ‘subject’ block will return:

module X
  private
    def build_them(type)
      puts 'Catching the star'
    end
end

describe 'public/private instance methods' do
  subject {
    extender = Class.new { extend(::X) }
    def extender.build
      puts "Throwing a star"
      build_them(type)
    end

    extender
  }

  it { should respond_to :build }
end

Note that describe must be used as the top level context, context must be nested