Mockito doNothing with Mockito.mockStatic

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I'm using Mockito, along with mockito-inline for mocking static methods. I'm trying to apply doNothing or similar behavior, to a static void method. The following workaround work, but I think that there should have a more convenient way to achieve this with less code.

try (MockedStatic<UtilCalss> mock = Mockito.mockStatic(UtilCalss.class)) {

     mock.when(() -> UtilCalss.staticMethod(any()))
            .thenAnswer((Answer<Void>) invocation -> null);

}

If it's a non-static method, we could simply do:

doNothing().when(mock).nonStaticMethod(any());

But I want to do the same for a static method.

2 Answers

You don't need to stub that call.

doNothing is a default behaviour of a void method called on a mock.

mockito-inline include mockito-core :

        <!-- Mockito-inline include Mockito-code in same version - Useful for Mock static method -->
        <!-- See https://asolntsev.github.io/en/2020/07/11/mockito-static-methods/ -->
        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-inline</artifactId>
            <version>3.6.28</version>
        </dependency>

And if static method you are testing return nothing => don't use mock.when => just execute the method you want to test and verify :

try (MockedStatic<UtilClass> mock = Mockito.mockStatic(UtilClass.class)) {

     mock.when(() -> UtilClass.staticMethod(any()))
            .thenAnswer((Answer<Void>) invocation -> null);

     App.main(null); // example : I'm testing main method from App class

     mock.verify(UtilClass::staticMethod); // I verify static method from UtilClass was called.

}

resources :

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