My JUnit test is failing with the following error: "java.lang.IllegalArgumentException: Could not find field [userRepository] of type [null] on target [com.clearsoft.demo.UserResource@756b2d90]"

Here is the Test class:

@RunWith(SpringJUnit4ClassRunner.class)

@SpringApplicationConfiguration(classes = App.class)

@WebAppConfiguration

@IntegrationTest

public class UserResourceTest {



    @Autowired

    private UserRepository userRepository;



    private MockMvc restUserMockMvc;



    @Before

    public void setup() {

        UserResource userResource = new UserResource();

        ReflectionTestUtils.setField(userResource, "userRepository", userRepository);

        this.restUserMockMvc = MockMvcBuilders.standaloneSetup(userResource).build();

    }



    @Test

    public void testGetExistingUser() throws Exception {

        restUserMockMvc.perform(get("/user/foo")

                .accept(MediaType.APPLICATION_JSON))

                .andExpect(status().isOk())

                .andExpect(content().contentType("application/json"))

                .andExpect(jsonPath("$.id").value(1));

    }

}

And here is the UserResource service:

@RestController

public class UserResource {



    @Autowired

    UserRepository repository;



    @RequestMapping(value = "/user/{email}", method = RequestMethod.GET)

    User hello(@PathVariable("email") String email) {

        return repository.findByEmailAddressAllIgnoringCase(email);

    }



}

Here is the repository:

public interface UserRepository extends Repository<User, Long> {



    Page<User> findAll(Pageable pageable);



    User findByEmailAddressAllIgnoringCase(String emailAddress);



}

And here is the Entity:

@Entity

@Table(name = "users")

public class User implements Serializable {

    /**

     * 

     */

    private static final long serialVersionUID = -1680480089065575997L;



    @Id

    @GeneratedValue(strategy = GenerationType.IDENTITY)

    @Basic(optional = false)

    @Column(name = "id")

    private Integer id;



    @Basic(optional = false)

    @NotNull

    @Size(min = 1, max = 255)

    @Column(name = "email_address")

    @Pattern(regexp = "[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\\."

            + "[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@"

            + "(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9]"

            + "(?:[a-z0-9-]*[a-z0-9])?", message = "{invalid.email}")

    private String emailAddress;



    public Integer getId() {

        return id;

    }



    public void setId(Integer id) {

        this.id = id;

    }



    public String getEmailAddress() {

        return emailAddress;

    }



    public void setEmailAddress(String emailAddress) {

        this.emailAddress = emailAddress;

    }



}

Here is the App class:

@SpringBootApplication

public class App implements CommandLineRunner {



    @Autowired

    UserRepository repository;



    public static void main(String[] args) {

        SpringApplication.run(App.class);

    }



    @Override

    public void run(String... strings) throws Exception {

        System.out.println("**************** RUN RUN RUN RUN");

        for (User user : repository.findAll(null)) {

            System.out.println("****************" + user.getEmailAddress());

        }

    }

}

Exception comes from this line:

ReflectionTestUtils.setField(userResource, "userRepository", userRepository);

Second parameter of setField method is a field name. UserResource has field "repository" - not "userRepository" as you try to set in your test.