Unit Tests How to Mock Repository Using Mockito - java

I am having an issue with stubbing my repository. I was suggested to just create another application.properties (which I have not done) and to use an in-memory database like H2. I was wondering though if I can just stub the call so when myDataService.findById(id) is called instead of it attempting to get that from the database just a mocked object can be returned?
I am new to writing mocks for my unit tests and spring boot in general so maybe I am missing something. Code below (tried to simplify and made names generic for posting here).
My test class
public class MyServiceImplTest
{
private MyDataService myDataService;
private NyService myService;
private MyRepository myRepository;
#Before
public void setUp() {
myDataService = Mockito.mock(MyDataServiceImpl.class);
myService = new MyServiceImpl(myDataService);
}
#Test
public void getById_ValidId() {
doReturn(MyMockData.getMyObject()).when(myDataService).findById("1");
when(myService.getById("1")).thenReturn(MyMockData.getMyObject());
MyObject myObject = myService.getById("1");
//Whatever asserts need to be done on the object myObject
}
}
Class used for making the service call to the data layer
#Service
public class MyServiceImpl implements MyService {
MyDataService myDataService;
#Autowired
public MyServiceImpl(MyDataService myDataService) {
this.myDataService = myDataService;
}
#Override
public MyObject getById(String id) {
if(id == null || id == "") {
throw new InvalidRequestException("Invalid Identifier");
}
MyObject myObj;
try {
myObj = myDataService.findById(id);
}catch(Exception ex) {
throw new SystemException("Internal Server Error");
}
return myObj;
}
}
This is where I am having the issue in my test. When the findById() method is called, the variable repository is null so when trying to do repository.findOne(id) it throws an exceptionn. This is what I am attempting to mock, but the repository is giving me issues.
#Repository
#Qualifier("MyRepo")
public class MyDataServiceImpl {
#PersistenceContext
private EntityManager em;
private MyRepository repository;
#Autowired
public MyDataServiceImpl(MyRepository repository) {
super(repository);
this.repository = repository;
}
public MyObject findById(String id) {
P persitentObject = repository.findOne(id);
//Calls to map what persitentObject holds to MyObject and returns a MyObject
}
}
Code for MyRepository here just to show it's an empty interface that extends CrudRepository
public interface MyRepository extends CrudRepository<MyObjectPO, String>, JpaSpecificationExecutor<MyObjectPO> {
}

Let me begin by saying you are on the right track by using Constructor Injection and not Field Injection(which makes writing tests with mocks much simpler).
public class MyServiceImplTest
{
private MyDataService myDataService;
private NyService myService;
#Mock
private MyRepository myRepository;
#Before
public void setUp() {
MockitoAnnotations.initMocks(this); // this is needed for inititalizytion of mocks, if you use #Mock
myDataService = new MyDataServiceImpl(myRepository);
myService = new MyServiceImpl(myDataService);
}
#Test
public void getById_ValidId() {
doReturn(someMockData).when(myRepository).findOne("1");
MyObject myObject = myService.getById("1");
//Whatever asserts need to be done on the object myObject
}
}
The call goes all the way from your service --> dataService. But only your repository calls are mocked.
This way you can control and test all the other parts of your classes(both service and dataService) and mock only repository calls.

Related

Junit Test Pass even when the method called inside may fail

I am creating a Junit Unit Test to check the createAccount method in service that calls Service a helper method. Please find it below.
Service class
public class AccountServiceImpl {
#Autowired
AccountHelper accountHelper;
#Override
public Account createAccount(Account account) throws CustomerNotFoundException {
accountHelper.checkAccountTypeForCustomer(account);
return accountRepository.save(account);
}
}
Helper Class:
public void checkAccountTypeForCustomer(Account acc) throws CustomerNotFoundException {
Boolean customerExists = customerRepository.existsById(acc.getCustomerId());
if(!customerExists) {
throw new CustomerNotFoundException("604", Message.CUSTOMER_NOT_FOUND);
}
}
AccountServiceTest class
#ExtendWith(MockitoExtension.class)
public class AccountServiceTest {
#Mock
private AccountRepository accountRepository;
#Mock
private CustomerRepository customerRepository;
#Mock
private AccountHelper accountHelper;
#InjectMocks
private AccountService testService;
#Test
void testCreateAccount() throws CustomerNotFoundException {
Account account = Account.builder().
accountType(AccountType.SAVINGS).
openingBalance(BigDecimal.valueOf(3000)).
ifsc("IFSC1").
customerId(1).
build();
testService.createAccount(account);
}
}
Above Test is passing although the customer is not present in the database.
The test is incomplete. But still the statement: testService.createAccount(account);
must fail as per my understanding.
Kindly correct me if I am wrong. I am relatively new to Junit.
However if I place the implementation for checkAccountTypeForCustomer() inside the service method instead of in the helper, the test case fails as expected.
The reason is that accountHelper is mocked in your test, which means that invocation of accountHelper.checkAccountTypeForCustomer(account) doesn't execute your business code.
I recommend you to use Spring mocking in this case, and to specify how your repository is expected to behave. It would look something like this:
#ExtendWith(SpringExtension.class)
class AccountServiceTest {
#MockBean
private CustomerRepository repository;
#Autowired
private AccountService testService;
#Test
void testCreateAccount() throws CustomerNotFoundException {
Mockito.when(repository.existsById(anyInt())).thenReturn(false);
...
CustomerNotFoundException thrown = Assertions.assertThrows(CustomerNotFoundException.class, () -> testService.createAccount(account));
Assertions.assertEquals("the exception message", thrown.getMessage());
}
}

How to mock mapstruct mapper output in a Spring Service?

I have a spring service (MyService) that uses a mapstruct mapper (CustomMapstructMapper) :
#Service
public class MyService {
private final ClassA classA;
private final ClassB classB;
/*
other private fields declarations...
*/
private CustomMapstructMapper customMapstructMapper = Mappers.getMapper(CustomMapstructMapper.class);
//MyService constructor
public MyService(final ClassA classA, etc...) {
this.classA = classA;
//etc...
}
public ServiceOutput mainMethod(some parameters) {
//some business logic
MyMapperOutput myMapperOutput = customMapstructMapper.map(MapperParameter parameter);
ServiceOutput serviceOutput = some business logic with myMapperOutput;
return serviceOutput;
}
}
I want to unit test MyService (I am using Junit 5) and mock my CustomMapstructMapper output without calling the real mapper during the test execution. I already have another test class that specificly test all the custom mappings in CustomMapstructMapper.
So I have this test class :
#ExtendWith(MockitoExtension.class)
class MyServiceTest {
#InjectMocks
private MyService myService;
#Mock
private CustomMapstructMapper customMapstructMapper;
#Mock
private MyMapperOutput myMapperOutput;
#Test
void testMyService() {
/*
Some mocks creation ..
*/
Mockito.when(myMapperOutput.getSomeField()).thenReturn("Some value");
Mockito.when(customMapstructMapper.map(Mockito.any(MapperParameter.class))).thenReturn(myMapperOutput);
ServiceOutput serviceOutput = myService.mainMethod(some parameters);
/*
Some assertions on serviceOutput
*/
}
}
When I run my test, the implementation of my mapper customMapstructMapperImpl is called in MyService, not my mock.
A NullPointerException is thrown in my mapper because some fields are not initiated.
I have tried to create a mock with the implementation of my mapstruct mapper :
#Mock private CustomMapstructMapperImpl customMapstructMapper;
but I get the same result.
What am I doing wrong?
You're not taking advantage of the spring framework and mapstruct support for it.
in your service change:
private CustomMapstructMapper customMapstructMapper = Mappers.getMapper(CustomMapstructMapper.class);
into
#Autowired
private CustomMapstructMapper customMapstructMapper;
If you don't have it yet at your mapper use
#Mapper( componentModel = "spring" )
This will cause the generated mapper to have the #Component annotation from the spring framework, and it becomes possible to auto-wire this.
After making these changes your method of supplying a mock for testing should work.
The code below works correctly. So maybe something else happened. Your code example is not quite complete.
#ExtendWith(MockitoExtension.class)
public class TestForService {
#InjectMocks
private Service service;
#Mock
private Mapper mapper;
#Test
public void test_service() {
System.out.println("test_service start");
Mockito.when(mapper.doSomeTh()).thenReturn("mock mapper doSomeTh");
String result = service.service();
System.out.println("test_service end, result: " + result);
}
static class Service {
private Mapper mapper = Mapper.getMapper();
public String service() {
System.out.println("Service.service");
return mapper.doSomeTh();
}
public void setMapper(Mapper mapper) {
this.mapper = mapper;
System.out.println("Service.setMapper: " + mapper);
}
}
static class Mapper {
public String doSomeTh() {
System.out.println("Mapper.doSomeTh");
return "mapper end";
}
public static Mapper getMapper() {
System.out.println("Mapper.getMapper");
return null;
}
}
}
result:
Mapper.getMapper
Service.setMapper: mapper
test_service start
Service.service
test_service end, result: mock mapper doSomeTh
A simpler way here:
Just add a package-private setter method into your MyService
// for testing only
void CustomMapstructMapper setCustomMapstructMapper(CustomMapstructMapper mapper) {
this.customMapstructMapper = mapper;
}
and inject your mocked CustomMapstructMapper in test code
#Test
void testMyService() {
/*
Some mocks creation ..
*/
Mockito.when(myMapperOutput.getSomeField()).thenReturn("Some value");
Mockito.when(customMapstructMapper.map(Mockito.any(MapperParameter.class))).thenReturn(myMapperOutput);
myService.setCustomMapstructMapper(customMapstructMapper); // inject your mocked customMapstructMapper here
ServiceOutput serviceOutput = myService.mainMethod(some parameters);
/*
Some assertions on serviceOutput
*/
}

First mock of the method applied always

I want to test a few cases in a method by mocking external dependency to return different results for every test case. But when always returns what is defined at first time (in this example - empty set) and that brokes the next tests.
If I run tests one by one they pass successfully but when I run the whole class only the first test pass and others fail.
Testing class:
class ExampleTest {
#Mock
private Dao dao;
#Mock
private Validator validator;
#Spy
#InjectMocks
Controller controller;
#BeforeEach
void setUp() {
initMocks(this);
}
private final static Set DATA = Set.of("data1", "data2");
#Test
void firstTest() throws UserDashboardException, DashboardException, WidgetException {
when(validator.filter(DATA)).thenReturn(Collections.emptySet());
assertThrows(Exception.class, () -> controller.create(DATA));
}
#Test
void secondTest() throws UserDashboardException, DashboardException, WidgetException {
when(validator.filter(DATA)).thenReturn(DATA);
controller.create(DATA);
verify(dao, times(1)).create(eq(DATA));
}
}
Tested class:
public class Controller {
private Dao dao;
private Validator validator;
public Controller(Dao dao,Validator validator) {
this.dao = dao;
this.validator = validator;
}
public String create(Set<String> data) {
data = validator.filter(data);
if (data.isEmpty()) {
throw new Exception("Invalid data.");
}
return dao.create(data);
}
}
So, in both tests create method throws an exception which is not what I expect. Maybe I miss some point?
Have you tried with doReturn method?
doReturn(DATA).when(validator).filter(DATA)
which can be import from org.mockito.Mockito.doReturn;
Edited: there might be a bug inside your code implementation:
data = validator.filter(data);

Mockito when isn't replacing original method behaviour

I got 2 modules User and Email, both of them have 1 entry point which is a facade, rest is package scoped. The configuration is done in 2 classes
#Configuration
class UserConfiguration {
#Bean
UserFacade userFacade(UserRepository repository, EmailFacade emailFacade) {
return new UserFacade(repository, emailFacade);
}
}
#Configuration
class EmailConfiguration {
#Bean
EmailFacade emailFacade(EmailSender emailSender) {
return new EmailFacade(emailSender);
}
}
Now, I want to write tests that don't require Spring to start. I implemented a simple InMemoryRepository to make this happen
#RunWith(MockitoJUnitRunner.class)
public class RegisterUserTest {
#Mock
private EmailFacade emailFacade = new EmailFacade(new FakeEmailSender());
#InjectMocks
private UserFacade userFacade = new UserConfiguration().userFacade(new InMemoryUserRepository(), emailFacade);
#Before
public void setUp() {
MockitoAnnotations.initMocks(this);
}
}
I need some fake objects to instantiate EmailFacade so I wrote fake implementation
public class FakeEmailSender implements EmailSender {
#Override
public void sendEmail(EmailMessage emailMessage) throws RuntimeException {
}
}
In that scenario, I'm testing User domain, so I want to mock Email anyways.
I wrote a test to check if it works
#Test
public void shouldReturnSendingFailed() {
Mockito.when(emailFacade.sendUserVerificationEmail(Mockito.any())).thenReturn(Either.left(EmailError.SENDING_FAILED));
assertThat(userFacade.registerNewUser(RegisterUserDto.builder()
.username(USERNAME_4)
.email(VALID_EMAIL)
.password(VALID_PASSWORD).build()).getLeft(), is(EmailError.SENDING_FAILED));
}
But it isn't... after running this test I got
java.util.NoSuchElementException: getLeft() on Right
edit#
regiserNewUser() method
Either<DomainError, SuccessMessage> register(RegisterUserDto registerUserDto) {
if(userRepository.findUser(registerUserDto.getUsername()).isPresent())
return Either.left(UserError.USERNAME_ALREADY_EXISTS);
var userCreationResult = User.createUser(registerUserDto);
var savedUser = userCreationResult.map(this::saveUser);
var emailDto = savedUser.map(this::createVerificationEmail);
return emailDto.isRight() ? emailFacade.sendUserVerificationEmail(emailDto.get())
: Either.left(emailDto.getLeft());
}
Edit2#
With following test configuration
#RunWith(MockitoJUnitRunner.class)
public class RegisterUserTest {
#Mock
private EmailFacade emailFacade;
#InjectMocks
private UserFacade userFacade = new UserConfiguration().userFacade(new InMemoryUserRepository(), emailFacade);
#Before
public void setUp() {
MockitoAnnotations.initMocks(this);
}
}
I got nullpointer here, last line of registerNewUser().
Try running this code
#RunWith(MockitoJUnitRunner.class)
public class RegisterUserTest {
#Mock
private EmailFacade emailFacade;
private UserFacade userFacade;
#Before
public void setUp() {
userFacade = new UserConfiguration().userFacade(new InMemoryUserRepository(), emailFacade);
}
}
There are a few issues with your code:
You initialize your mocks twice. You don’t need to call initMocks in the setUp method if you are using Mockito runner
You are trying to inject mocks to already initialized object. But the field you are trying to inject is also passed to the constructor. Please read #InjectMocks doc, to check the strategies used to inject the mocks:
constructor (not used here, already initialized object)
setter (do you have one?)
field (is it not final)
There are details to each strategy (see my questions above). If no staregy is matched, Mockito will fail silently. The fact that you are passing an object in constructor, and rely on setter or field injection afterwards makes this code unnecesarily complex.

How to inject a mock object to a class when testing?

My user class is as follows,
public class UserResource {
#Inject UserService userService;
public boolean createUser(User user) {
DbResponse res = userService.addUser(user);
if(res.isSuccess){
return true;
}else{
return false;
}
}
}
My test class looks as follows,
public class UserResourceTest {
UserResource userResource;
#BeforeMethod
void beforeMethod() {
userResource = new UserResource();
}
#Test
public void test() {
User user= mock(User.class);
boolean res= userResource.createUser(user);
assert(res);
}
}
As you can see a UserService object should be injected into the UserResource class. How can I inject a mock UserService object to userResource object inside my test?
FYI:
This is part of a Jersey JAX-RS project.
I'm using Java CDI, mockito and testNG (as the test library).
Consider using explicit dependency principal via constructor injection as it states very clearly what is required by the class in order to perform its particular function.
public class UserResource {
private UserService userService;
#Inject
public UserResource(UserService userService) {
this.userService = userService;
}
public boolean createUser(User user) {
DbResponse res = userService.addUser(user);
if(res.isSuccess){
return true;
}else{
return false;
}
}
}
and mock the UserService as well and assign it to the subject under test. Configure the desired/mocked behavior for the test.
public class UserResourceTest {
#Test
public void test() {
//Arrange
boolean expected = true;
DbResponse mockResponse = mock(DbResponse.class);
when(mockResponse.isSuccess).thenReturn(expected);
User user = mock(User.class);
UserService mockService = mock(UserService.class);
when(mockService.addUser(user)).thenReturn(mockResponse);
UserResource userResource = new UserResource(mockService);
//Act
boolean actual = userResource.createUser(user);
//Assert
assert(expected == actual);
}
}
Although I completely support the answer of #Nkosi I'd like to add this for completeness:
Use Mockitos JUnitRule to reate the mocks as described here: http://www.vogella.com/tutorials/Mockito/article.html :
public class UserResourceTest {
#Rule
public MockitoRule mockitoRule = MockitoJUnit.rule();
#Mock
private DbResponse mockResponse;
#Mock
private UserService mockService;
#Test
public void test() {
//Arrange
boolean expected = true;
when(mockResponse.isSuccess).thenReturn(expected);
when(mockService.addUser(user)).thenReturn(mockResponse);
// ...
Also then you could also use Mockitos #InjectMocks annotation like this:
public class UserResourceTest {
#Rule
public MockitoRule mockitoRule = MockitoJUnit.rule();
#Mock
private DbResponse mockResponse;
#Mock
private UserService mockService;
#InjectMocks
private UserResource userResource; // do not instantiate in test method
// ...
But I personally would discourage from it.
Yes, it is more convenient since it determines by reflection which dependency injection method you use. But if you don't have a "seam" to inject a certain dependency (neither Costructor parameter, non final property nor setter of matching type) you don't get a compile error which I personally find problematic.

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