Use Mockito to mock some methods but not others

Mockito is a Java mocking framework that allows you to create mock objects for testing. You can use Mockito to mock some methods of an object but not others by using the following steps:

  1. Create a mock of the object using the Mockito.mock() method:
MyObject mock = Mockito.mock(MyObject.class);
  1. Use the Mockito.when() method to specify the behavior of the mock for the methods that you want to mock:
when(mock.getValue()).thenReturn(10);
when(mock.getString()).thenReturn("Mocked");
  1. Use the Mockito.doCallRealMethod() method to specify that the mock should call the real implementation of the method:
doCallRealMethod().when(mock).doSomething();
  1. Use the mock object in your test as you would any other object:
int result = mock.getValue();  // returns 10
String str = mock.getString(); // returns "Mocked"
mock.doSomething();            // calls the real implementation

Keep in mind that you should use mocking sparingly, and only for isolated units of code. Overuse of mocking can lead to fragile and untestable code.