generate_response_message

# File actionpack/lib/action_dispatch/testing/assertions/response.rb, line 89
        def generate_response_message(expected, actual = @response.response_code)
          lambda do
            (+"Expected response to be a <#{code_with_name(expected)}>,"              " but was a <#{code_with_name(actual)}>").
              concat(location_if_redirected).
              concat(exception_if_present).
              concat(response_body_if_short)
          end
        end