CODEWITHSUNDEEP
javaunit-testing
Raicky Derwent
Raicky Derwent

Reputation: 393

Proper usage of Mockito.verify

I'm new to unit testing and i had a simple question regarding the usage of verify method used in Mockito. here's the class i used for testing.

public class Foo{
int n = 0;
void addFoo(String a){
    if(a == "a")
    add(1);
}

protected void add(int num){
    n =1;
}

public int get(){
    return n;
}

}

And here's my Unit test.

public class FooTest {
@Mock Foo f;

@Test
public void test() {
    MockitoAnnotations.initMocks(this);
    f.addFoo("a");

    //Passes
    Mockito.verify(f).addFoo("a");

    //Fails
    Mockito.verify(f).add(1);
}

}

And i get a 

   Wanted but not invoked:
f.add(1);
-> at FooTest.test(FooTest.java:22)

However, there were other interactions with this mock:
-> at FooTest.test(FooTest.java:16)

exception.

How do you verify that add(int num) is called ?

Upvotes: 1

Views: 643

Answers (1)

Mureinik
Mureinik

Reputation: 311143

I think you misunderstood the point of verify. In your test, Foo f is a mock object - Foo's internal implementation is ignored, and only the behavior you recorded on it (using when(f.someMethod().thenXXX) would happen.

The point of mocking and verifying is to test interactions while ignoring the internal implementation. In this example, you would probably have another class that uses Foo, and you'd want to test whether it invokes the correct methods of the given Foo instance.

Quick example:

Assume you have a class the uses the Foo class you presented in your question:

public class FooUser {
    private Foo f;

    public void setFoo(Foo f) {
        this.f = f;
    }

    public Foo getFoo() {
        return f;
    }

    public void addToFoo(String string) {
        f.add(string);
    }
}

Now, you'd want to test that FooUser#addToFoo(String) indeed invokes the correct add(String) method of Foo:

@RunWith (MockitoJUnitRunner.class)
public class FooUserTest {
    @Mock Foo f;
    FooUser fUser;

    @Before
    public void init() {
        fUser = new FooUser();
        fUser.setFoo(f);
    }

    @Test
    public void test() {
        fUser.addToFoo("a");
        Mockito.verify(f).addFoo("a");
    }

Upvotes: 3

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