### Question:
DataObjectValidationServiceImpl implements DataObjectValidationService { public Collection<ValidationMessage> validateObjectPropertyDeletion(final DataObject dataObject, final ObjectProperty objectProperty) { return objectPropertyDeleteValidators .stream() .flatMap(c -> c.validate(dataObject, objectProperty).stream()) .collect(Collectors.toList()); } DataObjectValidationServiceImpl(); @Inject  DataObjectValidationServiceImpl(final Instance<ObjectPropertyDeleteValidator> objectPropertyDeleteValidatorInstance); Collection<ValidationMessage> validateObjectPropertyDeletion(final DataObject dataObject,
                                                                        final ObjectProperty objectProperty);  }### Answer:
@Test public void validateObjectPropertyDeletion() { Collection<ValidationMessage> result = validationService.validateObjectPropertyDeletion(new DataObjectImpl(), new ObjectPropertyImpl()); assertEquals(2, result.size()); assertTrue(result.contains(message1)); assertTrue(result.contains(message2)); }