Spy with Mockito - Spy vs Mock

[@rohitrox8]

I was literally suffering to understand spy by words. Thanks to you now!

[@kekiir]

clear explanation!

[@AhmadShahwaiz]

Beautifully explained

[@RamapatiMaurya]

A person can learn more and put more attention if you show him/ her with error cases. Better to do like that way

[@umeshkumarroy5804]

Really Great

[@shankars4281]

So, when we use mock, we can't do below thing, since we it doesn't creates real object? List arrayList = mock(ArrayList.class); arrayList.add("sss"); assertEquals(1,arrayList.size());

[@thegamerz5034]

Yes, when we use Mock, we can't do below thing. This is because to create a stub of a specific method of a class, the return type needs to be the same as the real implementation. List.add() returns a boolean and not a new list with the added object. This makes it so that we can't return a list with "sss" when we do .add for a Mocked arraylist. For example: //Spy: //Given List spyArrayList = Mockito.spy(new ArrayList()); //When spyArrayList.add("sss"); //Then assertEquals(1, spyArrayList.size()); // This will return true. // For a mock, you need to DEFINE a stub // for each method. Because the logic is gone. // You have to specifically tell what outcome it should return for a specific input. //Mock: //Given List mockArrayList = Mockito.mock(ArrayList.class); List listWeWantNack = new ArrayList(List.of("sss")); //Next line doesn't work, since we can't specify a return type of arraylist, //because .add expects a boolean back. //This means we can't return an added list of stuff, because we can't override the .add method of list. //Mockito.when(mockArrayList.add("sss")).thenReturn(listWeWantNack); Sidenote: A Spy gives the same utility as the real implementation as you can see in the example, but you can specifically stub specific methods with a spy. This is quite powerful, since you don't have to specify what to return for every method of a mocked class, unlike a Mock where you have to specify what to return for EVERY method. This is why a Spy is called "partially mocked".

[@MaggicBones]

A M A Z I N G !!!

[@chaitanyabag7348]

Good and comprehensive video

[@prasannakumarattuluri7650]

its a good tutorial and clear one :)

[@SanjeevSharma123]

great videos thank you :)

[@maheshbeesetty5979]

Great

[@preethikashenoy]

Please add a tutorial on mocking SQLiteDatabase. Thanks in advance.

[@ShahidKhan-qx5fh]

python add is so annoying ....