Unit testing field validation with MockMvc but without Spring context? - validation

Question

Is it possible to test #Valid annotations using MockMvc and MockitoJUnitRunner? I can test most of the behavior of my CRUD controller but validation seems to require the use of Spring's JUnit runner, building the entire context and creating the JPA repo implementation which requires a lot of stuff.
The test below tries to test a POST method receiving a Customer entity where the firstName field is annotated with #Size(min=2, max=20). The result is
java.lang.AssertionError: View name expected:<edit> but was:<redirect:/info>
So the validation did not run.
#RunWith(MockitoJUnitRunner.class)
public class DataControllerTest {
#Mock
CustomerRepository mockRepo;
#InjectMocks
private DataController controller;
MockMvc mockmvc;
#Before
public void init() {
MockitoAnnotations.initMocks(this);
mockmvc = MockMvcBuilders.standaloneSetup(controller).build();
}
#Test
public void testBadSubmit() throws Exception {
mockmvc.perform(MockMvcRequestBuilders.post("/edit/1")
.param("firstName", "a"))
.andExpect(MockMvcResultMatchers.view().name("edit"));
Mockito.verifyZeroInteractions(mockRepo);
}
}
Controller class:
#Controller
public class DataController {
#Autowired
public CustomerRepository crep;
...
#RequestMapping(value = {"/edit/{id}"}, method = RequestMethod.POST)
public String add(Model model, #Valid Customer customer, Errors result) {
if (result.hasErrors()) {
return "edit";
}
crep.save(customer);
return "redirect:/info";
}
Entity:
#Entity
public class Customer {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id = null;
#Column(length=20)
#Size(min=2, max=20)
private String firstName;
...
}
JPA Repository interface:
#Repository
public interface CustomerRepository extends JpaRepository<Customer, Long> {
List<Customer> findByLastName(String lastName);
}

Answer 1

The purpose of the SpringJUnit4ClassRunner is to automatically load the application context and wire up everything automatically. You should be able to use MockitoJUnitRunner but you'll have to load the application context you want to use manually in your test. Regardless, however, you do need to load an application context, because calling DataController#add() through Spring is the only way that the #Valid annotation will be processed.
EDIT: If the real problem here is loading the JPA repository, you can use MockitoJUnitRunner and just load a test application context where a mock JPA repository is manually wired in, at little to no expense.