Power of Mockito.

1. Spy
@Spy

ClassToBTested classToBTested= new ClassToBTested();

2. Call RealMethod

@Mock mockedClass

when(mockedClass).doSomething(<AnyArg>).thenCallRealMethod.

3. Argument capturing:

ArgumentCaptor< ArgumentClass1 > captor1= ArgumentCaptor.forClass(ArgumentClass1.class);

ArgumentCaptor< ArgumentClass2> captor2 =ArgumentCaptor.forClass(ArgumentClass2.class);

classToBTested.testSomeMethod(someArgument);

Mockito.verify(classToBTested).doSometing(captor1.capture(), captor2.capture()));

ArgumentClass1 argumentObj1 = captor1.getValue();

ArgumentClass2 argumentObj2 = captor2.getValue();

//Assert argumentObj1 data here

4. Avoid Spy Objects from invocation during mocking:

doReturn("xyz").when(mockedClass).invokingSomeOtherMethod().

when(mockedClass).invokingSomeOtherMethod().thenReturn("xyz");

5. Mocking new instance creation:

@RunWith(PowerMockRunner.class)

@PrepareForTest(ClassToBeTested.class)

public class ClassToBeTested Test {

    private ClassToBeTested classToBeTested;

    @Before

    public void setUp() {

        classToBeTested = new ClassToBeTested();

    }

    @Test

    public void testSomeBehaviour() throws Exception {

        InternalClass internalClassObj = mock(InternalClass.class);//new InternalClass();

        PowerMockito.whenNew(InternalClass.class)

            .withAnyArguments().thenReturn(internalClassObj);

      classToBeTested.invokeBehaviourToBeTested();

 //verify the argument is internalClassObj

assert captor.getValue() equalsTo internalClassObj

doThrow(new Exception()).when(mockedObject).methodReturningVoid(...);