Hopelessly egocentric objects that make Rspec mock expectations explode.

hopelessly_egocentric_spec.rb

require 'spec_helper'

# https://github.com/raganwald-deprecated/homoiconic/blob/master/2009-02-02/hopeless_egocentricity.md
class HopelesslyEgocentric < BasicObject
  def method_missing(*args, &block)
    self
  end
  
  # These methods are required to make the tests output their failures normally.
  
  #def to_str
  #  'HopelesslyEgocentric'
  #end
  #def to_ary
  #  [self]
  #end
  #def to_int
  #  0
  #end
  
end

describe 'A test case for hopelessly egocentric objects' do
  let(:string) { 'a string' }
  let(:hopelessly_egocentric_object) { HopelesslyEgocentric.new }

  it 'can be used in successful expectations' do
    expect(string).to receive(:include?).with(hopelessly_egocentric_object)
    string.include? hopelessly_egocentric_object
  end

  it 'cannot be used as an argument in failing expectations' do
    expect(string).to receive(:include?).with(hopelessly_egocentric_object)
  end
  
  it 'cannot be involved in failing expectations' do
    expect(string).to receive(:include?).with(nil)
    string.include?(hopelessly_egocentric_object)
  end
end