How to mock JPA for Post method using mockito - spring

Question

Im trying to write the Unit test for a Create(Post) method which uses the JPA as DAO Layer .Im new to Mockito , hence insights needed .
1.EmployeeService .java
#Component("IEmployeeService ")
public class EmployeeService implements IInputService {
#Inject
EntityManagerFactory emf;
#PersistenceContext
EntityManager em;
public InputEntity create(InputEntity inputEntity) {
em = emf.createEntityManager();
try {
em.getTransaction().begin();
inputEntity.setLST_UPDTD_TS(new Date());
inputEntity.setLST_UPDTD_USER_ID(new String("USER1"));
em.persist(inputEntity);
em.getTransaction().commit();
} catch (PersistenceException e)
{
if (em.getTransaction().isActive()) {
em.getTransaction().rollback();
}
throw new WebApplicationException(e,Response.Status.INTERNAL_SERVER_ERROR);
}
finally {
em.close();
}
return inputEntity;
}
2.InputEntity.java is the Entity class with getters and setters for corresponding columns to employee age,salary ,etc .
Now if a Post method is called ,the create method in the EmployeeService class will be invoked .I have to write a unit test using mockito , and i m getting null-pointer , below is the test i wrote .
#Category(UnitTest.class)
#RunWith(MockitoJUnitRunner.class)
public class EmployeeServiceTest {
#Before
public void initMocks() {
MockitoAnnotations.initMocks(this);
}
#Autowired
EmployeeService employeeService;
#Mock
InputEntity inputEntity;
#Mock
EntityManagerFactory emf;
#Mock
private EntityManager em;
#Mock
private EntityTransaction et;
#Rule
public ExpectedException expectedException = ExpectedException.none();
#Test
public void test_create_employee_success() throws Exception {
InputEntity expected = Mockito.mock(InputEntity .class);
Mockito.when(em.getTransaction()).thenReturn(et);
Mockito.when(emf.createEntityManager()).thenReturn(em);
Mockito.doReturn(expected).when(employeeService).create(inputEntityMock);
InputEntity actual = new InputEntity();
Mockito.doReturn(actual).when(employeeService).create(inputFileRoleValidationMock);
assertEquals(expected, actual);
}

Answer 1

You have a local mock expected, that you are attempting to use in an assertEquals(), but that will never work because assertEquals uses Object.equals, and Mockito hijacks equals for internal uses. A Mockito mock will never Object.equals anything except itself.

Answer 2

We had the similar problem of NullPointerException and it was because of the entity manager. After we updated the connection properties in setUp method, we could able to call the JPA.
You can try to set the connection properties something like this.
//declare emfactory
private static EntityManagerFactory emfactory;
private static EntityManager em;
#BeforeClass
public static void setUp() throws Exception{
Map<Object, Object> properties = new HashMap<Object, Object>();
properties.put("openjpa.ConnectionURL",
"jdbc:db2://yourserver:port/DBName");
properties.put("openjpa.ConnectionUserName", "username");
properties.put("openjpa.ConnectionPassword", "userpassword");
//set Schema
//set Driver Name
emfactory = Persistence.createEntityManagerFactory("PersistenceUnitName",
properties);
em = emfactory.createEntityManager();
Mockito.when(emf.createEntityManager()).thenReturn(em);
}
Plus you need to modify your test_create_employee_success() to make this working. You are mocking everything in this method, which you should not do. You can try something like this.
#Test
public void test_create_employee_success() throws Exception {
{
InputEntity inputEntity = new InputEntity();
employeeService.create(inputEntity);
}

Answer 3

You need following changes in the code:
1.Instead of
#Autowired
EmployeeService employeeService;
You can use:
#InjectMocks
private EmployeeService EmployeeService;
Also as you are mocking in the method - InputEntity expected = Mockito.mock(InputEntity .class); you dont need at this declaration at the class level unless it is used in some other methods.
Also you can get rid of the declaration -
InputEntity actual = new InputEntity();
You can not assert mocked object and object using new keyword for equality.
Clean unit test will look like this -
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.runners.MockitoJUnitRunner;
#RunWith(MockitoJUnitRunner.class)
public class EmployeeServiceImplTest {
#Mock
private EntityManager em;
#Mock
private EntityManagerFactory emf;
#InjectMocks
private EmployeeService EmployeeService;
#Mock
private EntityTransaction et;
#Test
public void testCreate() throws Exception {
InputEntity expected = Mockito.mock(InputEntity.class);
Mockito.when(em.getTransaction()).thenReturn(et);
Mockito.when(emf.createEntityManager()).thenReturn(em);
EmployeeService.create(expected);
Mockito.verify(em, Mockito.times(1)).persist(expected);
}
}