@Test
 public void createValidThing() throws Exception {
   Thing thing = new Thing();
   thing.setName("simon");
   thing.setAmount(6);
   thing.setDueDate(Date.from(Instant.now().plus(1, ChronoUnit.DAYS)));
   thing.setTags(Collections.singletonList("super"));
   thingManager.create(thing);
 }
 @Test
 public void getWithoutValid() throws Exception {
   thingManager.get("2");
 }
 @Test(expectedExceptions = ConstraintViolationException.class)
 public void createInvalidThing() throws Exception {
   Thing thing = new Thing();
   thing.setDueDate(Date.from(Instant.now().minus(1, ChronoUnit.DAYS)));
   thingManager.create(thing);
 }