Org.mockito.exceptions.base.mockitoexception: failed to release mocks

org.mockito.exceptions.base.MockitoException: Failed to release mocks

The org.mockito.exceptions.base.MockitoException: Failed to release mocks exception occurs when there
is an issue with releasing the mock resources properly.

Mock objects are created for testing purposes and are used to simulate the behavior of real objects. These mock
objects need to be properly released after each test case to ensure clean and accurate testing environment.

Here’s an example that demonstrates the usage of mock objects and the potential cause of this exception:

        
class MyTestClass {
    private MyDependency myDependency;

    public MyTestClass(MyDependency myDependency) {
        this.myDependency = myDependency;
    }

    public void myTestMethod() {
        // Do something with myDependency
    }
}

class MyTestClassTest {
    private MyDependency mockDependency = Mockito.mock(MyDependency.class);
    private MyTestClass myTestClass = new MyTestClass(mockDependency);

    @Test
    public void testMyTestMethod() {
        // Perform test
    }
}
        
    

In the above example, we have a MyTestClass that depends on a MyDependency. In the
test class MyTestClassTest, we are creating a mock object of MyDependency using
Mockito’s mock method. The mock object is then passed to the constructor of MyTestClass
for testing.

The issue arises when the myDependency mock object is not properly released after the test case
execution. If the test case modifies the state of the mock object or performs any interactions with it, failing
to release the mock object can lead to unexpected behavior in subsequent test cases.

To fix this issue, make sure to release the mock objects properly. Mockito provides the MockitoAnnotations
class and the @MockitoAnnotations.initMocks annotation to automatically release the mock objects
after each test case. Here’s an updated version of the test class that properly releases the mock object:

        
class MyTestClassTest {
    @Mock
    private MyDependency mockDependency;

    @InjectMocks
    private MyTestClass myTestClass;

    @Before
    public void setup() {
        MockitoAnnotations.initMocks(this);
    }

    @Test
    public void testMyTestMethod() {
        // Perform test
    }
}
        
    

In the updated version, we are using the @Mock annotation to create the mock object and the
@InjectMocks annotation to inject the mock object into the myTestClass field. The
@Before annotated setup() method is used to initialize the mock objects using
MockitoAnnotations.initMocks(this).

By following this approach, the mock objects will be properly released after each test case, avoiding the
org.mockito.exceptions.base.MockitoException: Failed to release mocks exception.