# File test/unit/assertions.rb, line 97

                        def assert_instance_of(klass, object, message="")

                                _wrap_assertion {

                                        assert_equal(Class, klass.class, "assert_instance_of takes a Class as its first argument")

                                        full_message = build_message(message, object, klass, object.class) {

                                                | arg1, arg2, arg3 |

                                                "<#{arg1}> expected to be an instance of\n" + 

                                                "<#{arg2}> but was\n" +

                                                "<#{arg3}>"

                                        }

                                        assert_block(full_message) {

                                                klass == object.class

                                        }

                                }

                        end