Using Mockito to mock a class method inside another class

Question

I\'m trying to write unit tests with Mockito / JUnit for a function like this:

class1 {
 method {
  object1 = class2.method // method that I want to fake the ret         


        

Answer 1

I wrote a simple example which worked fine, hope it helps:

method1() from Class1 calls method2() from Class2:

    public class Class1 {
        private Class2 class2 = new Class2();
        public int method1() {
            return class2.method2();
        }
    }

Class2 and method2() :

    public class Class2 {
        public int method2() {
            return 5;
        }
    }

And the Test:

    import org.junit.Rule;
    import org.junit.Test;
    import org.mockito.InjectMocks;
    import org.mockito.Mock;
    import org.mockito.junit.MockitoJUnit;
    import org.mockito.junit.MockitoRule;

    import static org.junit.Assert.assertEquals;
    import static org.mockito.Mockito.when;

    public class TestClass1 {

        @Mock
        Class2 class2;

        @InjectMocks
        Class1 class1;

        @Rule
        public MockitoRule mockitoRule = MockitoJUnit.rule();

        @Test
        public void testMethod1(){
            when(class2.method2()).thenReturn(29);
            assertEquals(29,class1.method1());
        }
    }