实例化jUnit测试类

Question

I have a jUnit class extending a class whose protected methods I need to test.

@RunWith(...)
@Configuration(...)
public class testA extends A{
    @Test
    public void testProtectedMethod1(){
    .. 
    }
}

Now, the class A needs a certain variable (a DAO) to be set while instantiation. Running this code throws IllegalArgumentException - DAO must be provided.

Things I have tried :

1) Manually setting the DAO using @Before - didn't work

2) Specifying a bean for the test class with DAO's property set - didn't work.

How can I instantiate this jUnit class with an inherited property?

Answer 1

Your class under test should probably not be one you are inheriting from in your Unit test class. Also, testing private methods is inherently difficult (if not impossible) because of the way that JUnit (and indeed Java) are designed.

The whole point of using a unit tests and TDD is to be able to test the public methods of your class under test. If you are trying to test a private method, you probably want to rethink your (functional) class design in the first place. Is it following the Single Responsibility Principle ?

If you wish to make an exception to the general rule that we only test public methods, perhaps make your private method protected or package access (and make sure your test class has the same package name as your class under test).

Either way, it is bad practice in JUnit to have your test class inherit from your class under test and you should avoid that.

Answer 2

It turns out that I cannot inject any property of a jUnit test class because its object is instantiated by jUnit runtime itself. Anyway, I ended up using reflection to test the private methods.