Exception : mockito wanted but not invoked, Actually there were zero interactions with this mock

Question

I have interface

Interface MyInterface {
  myMethodToBeVerified (String, String);
}

And implementation of interface is

class MyClassToBeTested implements MyInterface {
   myMethodToBeVerified(String, String) {
    …….
   }
}

I have another class

class MyClass {
    MyInterface myObj = new MyClassToBeTested();
    public void abc(){
         myObj.myMethodToBeVerified (new String(“a”), new String(“b”));
    }
}

I am trying to write JUnit for MyClass. I have done

class MyClassTest {
    MyClass myClass = new MyClass();
  
    @Mock
    MyInterface myInterface;

    testAbc(){
         myClass.abc();
         verify(myInterface).myMethodToBeVerified(new String(“a”), new String(“b”));
    }
}

But I am getting mockito wanted but not invoked, Actually there were zero interactions with this mock at verify call.

can anyone suggest some solutions.

Evadne

Answer 1

You need to inject mock inside the class you're testing. At the moment you're interacting with the real object, not with the mock one. You can fix the code in a following way:

void testAbc(){
     myClass.myObj = myInteface;
     myClass.abc();
     verify(myInterface).myMethodToBeVerified(new String("a"), new String("b"));
}

although it would be a wiser choice to extract all initialization code into @Before

@Before
void setUp(){
     myClass = new myClass();
     myClass.myObj = myInteface;
}

@Test
void testAbc(){
     myClass.abc();
     verify(myInterface).myMethodToBeVerified(new String("a"), new String("b"));
}

Endearment

Why can't we use Mockito.mock here? – Mazonson

@Mazonson : We can use Mockito.mock, for that we have to use one setter method for myObj and set the mocked object to myObj. – Deadeye

How is myClass.myObj = myInteface; valid? myObj is not a method of myClass – Railey

Answer 2

Your class MyClass creates a new MyClassToBeTested, instead of using your mock. My article on the Mockito wiki describes two ways of dealing with this.

Returnee

HikariDataSourceProvider dataSourceProvider = mock(DataSourceProvider.class); verify(dataSourceProvider).shutdown(); what is problem in it – Lenity

Answer 3

@Jk1's answer is fine, but Mockito also allows for more succinct injection using annotations:

@InjectMocks MyClass myClass; //@InjectMocks automatically instantiates too
@Mock MyInterface myInterface

But regardless of which method you use, the annotations are not being processed (not even your @Mock) unless you somehow call the static MockitoAnnotation.initMocks() or annotate the class with @RunWith(MockitoJUnitRunner.class).

Breannabreanne

Answer 4

@jk1 answer is perfect, since @igor Ganapolsky asked, why can't we use Mockito.mock here? i post this answer.

For that we have provide one setter method for myobj and set the myobj value with mocked object.

class MyClass {
    MyInterface myObj;

    public void abc() {
        myObj.myMethodToBeVerified (new String("a"), new String("b"));
    }

    public void setMyObj(MyInterface obj)
    {
        this.myObj=obj;
    }
}

In our Test class, we have to write below code

class MyClassTest {

MyClass myClass = new MyClass();

    @Mock
    MyInterface myInterface;

    @test
    testAbc() {
        myclass.setMyObj(myInterface); //it is good to have in @before method
        myClass.abc();
        verify(myInterface).myMethodToBeVerified(new String("a"), new String("b"));
     }
}

Deadeye

Answer 5

This exception can also be thrown if say, you expect thisMethod() to execute, but it didn't. It didn't because it's inside a condition that was not met.

For example, if you have some unit test that says verify thisMethod() is executed, but in fact, it was not because varX and varY are not equal.

//method expected to be called.    
if( varX == varY){
     thisMethod();
  }

 //test
 Mockito.verify(foo).thisMethod();

Compossible

Answer 6

This is because of your class was not invoked correctly. For example,

@Mock ClassName className;
.....verify(className).method(argument1, argument2);  //Actual code

In this case, className.class was not invoked for the junit. Make it to the following:

@Mock 
Class className;
.....
ClassName className = mock(ClassName.class);
verify(className).method(argument1, argument2);

Saritasarkaria