Mockito JUnit对引发异常的方法进行测试

Question

I have a method inside my service which throws exception for one method call. For example, I have a code like:

void myServiceMethod() {
    method1(); // passes

    method2(); // passes

    method3(); // throws exception

    method4(); // passes

    method5(); // passes
}

What I want, is to handle this method3 (in real program it is a static method), in some way, so that a program can continue executing further code such as method4 and method5 in this example.
Is it possible in mockito junit test, to return any value instead of exception, or to just skip it?

Answer 1

Your question is actually two:

1: how do I avoid execution the mocked method ?
2: how do I mock static methods?

Here are the answeres:

1. Mockito provides 2 APIs to configure your mock. The more common (and more readable) for is:

    when( mock.mockedMethod() ) .thenReturn(someValue); 

   The problem her is that the real method is actually executed and just the result is replaced. Usually this is not a problem unless your method throws an (unchecked) exception based on the return values of other (mocked but possibly unconfigured) methods in the same object or tries to access methods on dependencies of the mocked object since they are null so that a NPE is thrown.

   One way is to also configure return values for all the other methods in your mocked class. But then you have to "open" your mocked classes API bye raising the visibility of all methods involved above private just for testing. But making such changes just for testing is bad design.

   To avoid that you need to use the other form which does not execute the configured method:

    doReturn(someValue).when( mock ). mockedMethod(); 

   ^{please mind that the closing brace moved from behind the method call to before the dot separating the mock variable from the method call...}

   This might also solve your problem with the static method in your dependency in your concrete example.

---

2. You stated that the method you want to mock is static in your production code.

   The problem here is that you should not use static access in your code in the first place. So the best way is to change your method to an instance method and provide is instance of the class providing your "serviceMethod". Then you can use plain Mockito to create a mock and replace it for testing easily.

Some may argue you can use PowerMock to mock static and/or private methods. While this is technically true I'd consider it a surrender to your bad design ...