Question

I’m working through the about_classes.rb file in the Ruby Koans, and have hit a brick wall with the “inside_a_method_self_refers_to_the_containing_object” test. Here’s the code:

class Dog7
  attr_reader :name

  def initialize(initial_name)
    @name = initial_name
  end

  def get_self
    self
  end

  def to_s
    __
  end

  def inspect
    "<Dog named '#{name}'>"
  end
end

def test_inside_a_method_self_refers_to_the_containing_object
  fido = Dog7.new("Fido")

  fidos_self = fido.get_self
  assert_equal <Dog named 'Fido'>, fidos_self
end

So, I’m trying to make the first half of the assert_equal evaluate to the second half (fidos_self). When I work it out in irb, fidos_self returns <Dog named 'Fido'>, but I keep receiving a syntax error for that answer.

I’ve seen this similar post:
Ruby Koans: Where are the quotes in this return value?, but his solution (putting fido instead of <Dog named 'Fido'>) causes my rake to abort, saying the stack level is too deep.

This is driving me nuts. What am I missing here?

Answer 1

That isn’t valid syntax. Just because something shows up in IRB as a particular thing doesn’t mean that’s what it literally is. The inspect method is often over-written, and in this case it’s been remapped to something custom.

What you want is:

assert_equal "<Dog named 'Fido'>", fidos_self.inspect

By default any result in irb is presented by calling inspect.