Java tool for testing private methods?

Question

There are different opinions on the meaningfulness of testing of private methods, e.g., here and here. I personally think it makes sense, the question is how to do it properly.

Answer 1

it would be nice to be able to call private methods in the test code like

@MakeVisibleForTesting Something something = new Something();
Assert.assertEquals(43, something.internalSecret());

There's such thing as a method annotation, check out dp4j's @TestPrivates:

@Test
@TestPrivates 
//since the method is annotated with JUnit's @Test this annotation is redundant. 
// You just need to have dp4j on the classpath.
    public void somethingTest(){
      Something something = new Something();
      int sthSecret = something.internalSecret();
       Assert.assertEquals(43, sthSecret); //cannot use something.internalSecret() directly because of bug [dp4j-13][2] 
    }