NullpointerException mocking 测试

Question

I have a problem mocking the test, everything goes correct till this point of the code/test which i get a NullPointerException , this is the main code where launches the null pointer.

ResponseSrvAddDto responseSrvAdd = kjidR048.executeAddDocuments(requestAdd);
        
String returnCode = responseSrvAdd.getReturnCode();
if (returnCode != null && "00".equals(returnCode)){

ERROR! java.lang.NullPointerException

I have this in the test

ResponseSrvAddDto responseSrvAdd = mock(ResponseSrvAddDto.class);

Mockito.when(kjidR048.executeAddDocuments(requestAdd)).thenReturn(responseSrvAdd); (this goes correct)
String code = "00";
Mockito.when(responseSrvAdd.getReturnCode()).thenReturn(code); 

(but this looks like ignores the mock)

I don't know why having the mock in the responseSrvAdd.getReturnCode() launches a null pointer but i have this already mocked.

Answer 1

When you use mock on service it's create a object that do nothing or return null on all method. If you want to test responseSrvAdd.getReturnCode() use spy https://www.baeldung.com/mockito-spy here is guide.

For entity you need to create object it will be like this:

ResponseSrvAddDto responseSrvAdd = new ResponseSrvAddDto(); responseSrvAdd.setReturnCode("00"); Mockito.when(kjidR048.executeAddDocuments(requestAdd)).thenReturn(responseSrvAdd);