message: include missing input
diff: @@ -9,6 +9,9 @@ const App = () => {
  return (
  <form onSubmit={handleSubmit(onSubmit)}>
  + <input {...register('test')} />
  + {errors.username && <p>{errors.username.message}</p>}
  +
  <button
  type="button"
  onClick={() => {
  