gistfile1.rb

require 'rspec/core'

examples = RSpec.describe 'a "Hello world" object' do
  before(:each) do
    @hello_world = HelloWorld.new
  end

  it 'says "Hello world"' do
    raise unless @hello_world.message == 'Hello world'
  end
end

examples.run(RSpec.configuration.reporter) # fails

class HelloWorld
  def message
    'Hello world'
  end
end

examples.run(RSpec.configuration.reporter) # fails