List of Classes and Methods of org.mockitousage.bugs.injection package of Mockito Framework

In my case, I had a similar issue when I worked with JUnit5

@ExtendWith(MockitoExtension.class)
class MyServiceTest {
...

@InjectMocks
MyService underTest;

@Test
void myMethodTest() {
...
}

underTest was null. The cause of the problem was that I used @Test from JUnit4 package import org.junit.Test; instead JUnit5 import org.junit.jupiter.api.Test;

The following, running under Mockito 1.9.0 and JUnit 4.8.2, does not print anything to my console:

import static org.mockito.Mockito.*;

import org.junit.Test;

public class TestNonCall {
  public class TestClass {
    public String test() {
      System.out.println("test called!");
      return "test";
    }
  }

  @Test
  public void doTest() {
    final TestClass mock = mock(TestClass.class);

    when(mock.test()).thenReturn("mock!");
  }
}

Further, if I put a breakpoint in the test() method it is never hit.

Perhaps post more code? It looks like your example is not complex enough to demonstrate the behaviour you're having problems with.

Also: are you using the latest version of Mockito?

Edit: New Thought: Are You Mocking a Final Method?

If you add a final modifier to the method you are mocking, you get the behaviour you reported.

This is because Mockito does not mock final and static methods. Instead, it delegates the calls to the real implementation.

Might your actual code be attempting to mock a final method?

If so, you can use PowerMock, which is an extension to Mockito that allows mocking final methods.

You would need to add the following annotations to your test case class:

@RunWith(PowerMockRunner.class)
@PrepareForTest(TestClass.class)
public class TestNonCall {
  // ...
}

and mock the class using the PowerMock method in your test method:

final TestClass mock = PowerMockito.mock(TestClass.class);

then proceed as usual.

I think you do need to cast it, but it shouldn't be too bad:

Foo<Bar> mockFoo = (Foo<Bar>) mock(Foo.class);
when(mockFoo.getValue()).thenReturn(new Bar());

For functions returning void, use doAnswer()

doAnswer(...).when(mockedObject).handle(any(Callback[].class));

And an Answer that performs the interception must go in as the parameter to doAnswer, e.g. as an anonymous class:

new Answer() {
  public Object answer(InvocationOnMock invocation) {
      Object[] args = invocation.getArguments();
      Mock mock = invocation.getMock();
      return null;
  }}

In this case args will be the array Callback[]!

Try this:

@RunWith(MockitoJUnitRunner.class)
public class AvailabilityTest {
    @InjectMocks
    @Spy
    private Availability availability = new Availability();

    @Test
    public void testGetStockLevelStage() {
       Mockito.doReturn(expectedLong).when(availability).getStockLevelLimit();
       availability.getStockLevelStage();
    }
}

Here is an article I wrote on Mockito Spying if you need a further read.

@Mock creates a mock. @InjectMocks creates an instance of the class and injects the mocks that are created with the @Mock (or @Spy) annotations into this instance.

Note you must use @RunWith(MockitoJUnitRunner.class) or Mockito.initMocks(this) to initialize these mocks and inject them (JUnit 4).

With JUnit 5, you must use @ExtendWith(MockitoExtension.class).

@RunWith(MockitoJUnitRunner.class) // JUnit 4
// @ExtendWith(MockitoExtension.class) for JUnit 5
public class SomeManagerTest {

    @InjectMocks
    private SomeManager someManager;

    @Mock
    private SomeDependency someDependency; // this will be injected into someManager
 
     // tests...

}

You can implement this test functionality this way (Java 8):

myMock
    .expect(requestTo("http://myfakeurl.blabla"))
    .andExpect(method(HttpMethod.GET))
    .andRespond(request -> {
        try {
            Thread.sleep(TimeUnit.SECONDS.toMillis(1));
        } catch (InterruptedException ignored) {}
        return new MockClientHttpResponse(myJsonResponse, HttpStatus.OK);
    });

But, I should warn you, that since MockRestServiceServer simply replaces RestTemplate requestFactory any requestFactory settings you'd make will be lost in test environment.

If you find yourself creating test classes (other than the classes containing actual tests), then you've defeated the purpose of having a mocking framework.

Create your mocks in your testcases:

 @Test
 public void testGreetingGenerator() {
      Person mockPerson = mock(Person.class);
      when(mockPerson.getName()).thenReturn("Alan");

      GreetingGenerator greeting = new GreetingGenerator(mockPerson);
      assertEquals("Hello Alan", greeting.getGreeting());
 }

If you are using the same mock in many tests, by all means make the mock a field, and put the mock creation into an @Before method.

 @Before
 public void setUp() {
      mockPerson = mock(Person.class);
      when(mockPerson.getName()).thenReturn("Alan");
 }

 @Test
 public void testGreetingGenerator() {
      GreetingGenerator greeting = new GreetingGenerator(mockPerson);
      assertEquals("Hello Alan", greeting.getGreeting());
 }

You can create a "basic" mock in setUp() and add more mocked behaviour to it in the individual testcases. Remember that setUp() gets called before each test, so you get fresh objects in each test.

If the mock creation gets too long and complex, it's fine to move it into a method (static or otherwise), and if necessary decompose that method into lots of smaller ones.

However, if your test code gets too complicated, think of it as a warning that perhaps the unit under test has too many dependencies and needs to be redesigned for testability.

Mocking is for unit testing. In the example above, the unit I am testing is GreetingGenerator. I am not intending to test Person here, so it is better to use a mock Person than a real one. That way if something about Person breaks, my Person tests will fail but my GreetingGenerator tests will keep working.

However that means that those tests don't validate that your Person and GreetingGenerator classes interoperate properly, and that's why as well as unit tests, you should have integration tests.

If you know a class is just for value objects, there's little benefit in using a mock.

Mockito/Hamcrest and generic classes

Yes, this is a general problem with Mockito/Hamcrest. Generally using isA() with generic classes produces a warning.

There are predifined Mockito matchers for the most common generic classes: anyList(), anyMap(), anySet() and anyCollection().

Suggestions:

anyIterable() in Mockito 2.1.0

Mockito 2.1.0 added a new anyIterable() method for matching Iterables:

when(client.runTask(anyString(), anyString(), anyIterable()).thenReturn(...)

Ignore in Eclipse

If you just want to get rid of the warning in Eclipse. Option exists since Eclipse Indigo:

Window > Preferences > Java > Compiler > Errors/Warnings > Generic types > Ignore unavoidable generic type problems

Quick Fix with @SuppressWarnings

I suggest you do this if you have the problem only once. I personally don't remember ever needing an isA(Iterable.class).

As Daniel Pryden says, you can limit the @SuppressWarnings to a local variable or a helper method.

Use a generic isA() matcher with TypeToken

This solves the problem for good. But it has two disadvantages:

• The syntax is not too pretty and might confuse some people.
• You have an additional dependency on the library providing the TypeToken class. Here I used the TypeToken class from Guava. There's also a TypeToken class in Gson and a GenericType in JAX-RS.

Using the generic matcher:

import static com.arendvr.matchers.InstanceOfGeneric.isA;
import static org.mockito.ArgumentMatchers.argThat;

// ...

when(client.runTask(anyString(), anyString(), argThat(isA(new TypeToken<Iterable<Integer>>() {}))))
            .thenReturn(...);

Generic matcher class:

package com.arendvr.matchers;

import com.google.common.reflect.TypeToken;
import org.mockito.ArgumentMatcher;

public class InstanceOfGeneric<T> implements ArgumentMatcher<T> {
    private final TypeToken<T> typeToken;

    private InstanceOfGeneric(TypeToken<T> typeToken) {
        this.typeToken = typeToken;
    }

    public static <T> InstanceOfGeneric<T> isA(TypeToken<T> typeToken) {
        return new InstanceOfGeneric<>(typeToken);
    }

    @Override
    public boolean matches(Object item) {
        return item != null && typeToken.getRawType().isAssignableFrom(item.getClass());
    }
}