Spikes in Rspec/Given

sample.rb

# Spike in rspec-given

# The following now works in a proof of concept spike.
# When an exception happens during a When block (and there 
# result variable to catch it), the result will be a "Touchy" 
# object that re-raises the exception from the When block
# on every single method you could call on it.

describe "Empty Stack" do
  When(:result) { empty_stack.pop }

  # This fails because calling .nil? on the touchy object 
  # re-raises the exception.

  Then { result.should be_nil }

  # This passes because when the raise_error matcher attempts
  # to evaluate what it thinks is a lambda (but really is a Touchy
  # object) the expected exception is raised).

  Then { result.should raise_error(Stack::UnderflowError, /empty/) }

  # The raise_error matcher "reads funny" when given a result. We
  # could easily setup an alias for raise_error.

  Then { result.should have_failed(Stack::UnderflowError, /empty/) }
end

touchy.rb

      class Touchy < BasicObject
        def initialize(exception)
          @exception = exception
        end
        def method_missing(sym, *args, &block)
          ::Kernel.raise @exception
        end
      end