Injection of mocks doesn't work with when clauses - java

I have to test the following class, with an autowired object:
public class Provider {
#Autowired
private Service service;
public Provider() {}
public Provider(final Service service) {
this.service = service;
}
// Other code here
}
I created my test as follows:
#RunWith(PowerMockRunner.class)
public class ProviderTest {
#Mock(name="service") Service service;
#Mock Score score;
#InjectMocks Provider provider = new SearchResultProvider();
#Before
public void setup() {
when(service.process()).thenReturn(score);
}
#Test
public void my_test() {
provider.execute(); // It fails, because service.process() returns null
// Other code here
}
// Other tests here
}
However, when I run the test, it fails. Everything is fine, except the clause when(...) that seems to be ignored.
That causes the test to fail on the call to provider.execute(). Inside this function the call to service.process() is executed and then I would expect a "score mock" to be returned. But a null value is returned instead.
What have I done wrong?

The sample code show no need for powermock, I suppose there's PowerMock because some code is final. But the test don't prepare the classes to be definalized.
I will suppose the code with a final method is the Service
public class Service {
public final Score process() {
throw new NullPointerException("lol");
}
}
Then the code won't pass, unless the test prepares the classes to be definalized :
#RunWith(PowerMockRunner.class)
#PrepareForTest(Service.class)
public class ProviderTest {
...
}

Related

NullPointerException when doNothing() is called on Junit Mockito

I am writing a my unit test using Mockito but I am facing some error stubbing a method in the same class as my test class.
So basically, I am testing my service class MyService.class(Subject being tested) and this is how I am declaring my Mocks and #InjectMocks.
I am facing a null pointer whenever i hit the checkUserBackground() method when I am using doNothing() because the method returns void. I have also tried using verify() but I am getting error saying "Wanted but not invoked".
How do I get pass this error? Been stuck for 13 hours, appreciate some help thanks!
#ExtendWith(MockitoExtension.class)
#MockitoSettings(strictness = "Strictness.LENIENT")
class MyServiceTest {
#InjectMocks
private MyService myService;
#Test
void testCreateUser() {
User user = new User();
user.setAge(25);
user.setName(Jack);
Mockito.doNothing().when(myService).checkUserBackground(user.getName(), true);
assertEquals(myService.createUser().getName(), "Jack");
}
}
This is the actual Service class:
class MyService() {
public static void createUser(User user) {
checkUserBackground(user.getName(), true); //Null Pointer here
}
public void checkUserBackground(String name, Boolean newUser){
//some logic which doesnt matter
}
}
Annotation #InjectMock is for dependency injection - its real class bean. But later in method you try mock method of injected bean.
In your case will be enougth when you add method instead annotation:
#Before
public void init() {
myService = Mockito.mock(MyService.class)
}

Mockito - underlying service is null

I have a Service A which autowired Service B and is using a method from Service B.
Service B autowired another Service C and is using a method from it.
I am writing a test for Service A and the test fails at the call where Service B is invoked.At this point Service C is null.
I have tried #Mock for Service B. Nothing seems to work. How can i successfully test this service which is failing on a service that it isnt explicitly autowiring.
//Service A
#Service
public class FileServiceImpl{
#Autowired
private FileNameServiceImpl fileNameService;
public void createFile(String fileName){
String targetFileName = fileNameService.getTargetFileName(fileName);
}
}
//Service B
#Service
public class FileNameServiceImpl{
#Autowired
private CustomDateService customDateService
public String getTargetFileName(String fileName){
return fileName + customDateService.getCustomDate();
}
}
//CustomDate - this is an interace. The Impl is in another package.
public interfaceCustomDateService{
public String getCustomDate();
}
I am trying to test FileServiceImpl , however it fails with a NullPointer Exception because customDateService is null.
Even though, FileServiceImpl is not calling customDateService.
This is what I have for test thus far:
#Category(UnitTest.class)
#RunWith(MockitoJUnitRunner.class)
public class FileServiceImplTest {
#Spy
#InjectMocks
private FileServiceImpl fileServiceImpl;
#Mock
private FileNameServiceImpl fileNameService;
#Before
public void init() throws Exception {
MockitoAnnotations.initMocks(this);
}
#Test
public void testFileName() {
String fileName = "test1.txt";
fileServiceImpl.createFile(fileName); // Test Fails here
Mockito.validateMockitoUsage();
}
As Shane eluded, this sounds like you're maybe integration testing.
If so, make sure the context of your test encompasses the autowired components.
You should post some code, as it's hard to know what exactly is going on here.
If you aren't integration testing, don't rely on autowiring, just construct new ServiceA manually passing in a mocked ServiceB.
Also make sure to initialise your mocks.
private ServiceA serviceA;
#Mock
private ServiceB serviceB;
#BeforeEach
public void setUp() {
MockitoAnnotations.initMocks();
serviceA = new ServiceA(serviceB);
}
EDIT:
First of all, as good practice you should favor constructor injection over field injection in Spring.
So set up the service classes with Autowired constructors.
Also, I'm pretty sure with a mockito Spy you have to initialise the class.
If you switch to use constructor Autowiring you can inject the mocks manually.
#Category(UnitTest.class)
#RunWith(MockitoJUnitRunner.class)
public class FileServiceImplTest {
#Spy
private FileServiceImpl fileServiceImpl;
#Mock
private FileNameServiceImpl fileNameService;
#Before
public void init() throws Exception {
MockitoAnnotations.initMocks(this);
fileServiceImpl = new FileServiceImpl(fileNameService);
}
#Test
public void testFileName() {
String fileName = "test1.txt";
fileServiceImpl.createFile(fileName); <-- now this shouldn't fail
Mockito.validateMockitoUsage();
}

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.

Mockito to test an autowired field

public interface Dummy {
public returnSomething doDummyWork(arg1, agr2);
}
public class A implements Dummy {
#AutoWired
PrintTaskExecutor printTaskExecutor;
public returnSomething doDummyWork(arg1, agr2) {
callingVoidMethod();
return something;
}
public void callingVoidMethod() {
printTaskExecutor.printSomething(arg1, arg2);
}
}
public class testDummy {
#Autowired
Dummy dummyA//this bean is configured in ApplicationContext.xml and it works fine.
#Mock
PrintTaskExecutor printaskExecutor;
#Before
public void initMocks() {
MockitoAnnotations.initMocks(this);
printaskExecutor = Mockito.mock(PrintTaskExecutor.class);
Mockito.doNothing().when(printaskExecutor).printSomething(anyString(), anyString());
}
#Test
Public void testA
{
Dummy.doDummyWork(arg1, arg2);//I m giving actual arguments
//instead of moocking it calls the original method.
Mockito.verify(printaskExecutor, times(1)).printSomething(anyString(), anyString());
}
}
I have an autowired TaskExecutor in the class I m testing and I want to mock it.I have tried this in my code and It calls the actual method instead of do nothing and in the verify it errors out saying no interactions happened. How should I handle this situation?
I try to avoid using Mockito and Bean Containers together in one test. There are solutions for that problem. If you use Spring you should use #RunWith(SpringJUnit4Runner.class). More on this subject: Injecting Mockito mocks into a Spring bean
The clean way: Actually your class testDummy does not test Dummy but A. So you can rewrite your class in following way:
public class testA {
#Mock
PrintTaskExecutor printTaskExecutor;
#InjectMocks
A dummyA;
...
BTW: #Mock together with initMocks(this) and printaskExecutor = Mockito.mock(PrintTaskExecutor.class); do the same, you can skip the latter statement.

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