Mockito's `reset()` method is a feature that allows you to reset a mock object so it can be reused. However, its use is generally discouraged by Mockito developers and users, as it can indicate poorly designed tests or code that is overly complex and difficult to test cleanly[7][9]. Instead, the recommended approach is to create new mocks for each test method to ensure independence and clarity in testing[7][9].
Comparison with Other Mocking Libraries
1. JMock2: Unlike Mockito, JMock2 uses a context to manage expectations and mock information, which is rebuilt for each test method. This means that JMock2 does not require an explicit reset like Mockito does[10]. JMock2's approach helps maintain test isolation without needing to manually reset mocks.
2. EasyMock: EasyMock also does not typically require a reset method. It is designed to create new mock objects for each test, similar to the recommended practice with Mockito. Szczepan Faber, a Mockito developer, mentions that he never needed a reset feature while using EasyMock[8].
3. Mockito vs. Other Libraries: In general, other mocking libraries like JMock2 and EasyMock promote a cleaner testing approach by either automatically managing mock state or encouraging the creation of new mocks for each test. Mockito's `reset()` method is more of an exception rather than the norm in mocking frameworks.
Best Practices
- Avoid Using `reset()`: Unless absolutely necessary, such as when a mock is injected by a container and cannot be recreated for each test, it is advisable to avoid using `reset()`. Instead, focus on creating simple, focused tests with new mocks for each scenario[7][9].
- Use `clearInvocations()`: If you need to clear interactions without resetting stubbing, use `clearInvocations()`. This method allows you to preserve stubbing while clearing any recorded interactions, which can be useful in certain scenarios[5].
- Refactor Code for Testability: If you find yourself needing to use `reset()` frequently, it may indicate that your code could benefit from refactoring to make it more testable. This could involve breaking down complex methods or improving dependency injection[9].
In summary, while Mockito provides a `reset()` method, its use is generally discouraged in favor of creating new mocks for each test. Other mocking libraries often promote similar practices, emphasizing clean and independent tests over complex mock management.
Citations:[1] https://www.tutorialspoint.com/mockito/mockito_resetting_mock.htm
[2] https://groups.google.com/g/mockito/c/Y_IhdC8Lx_M
[3] https://www.vogella.com/tutorials/Mockito/article.html
[4] https://www.lambdatest.com/automation-testing-advisor/selenium/methods/org.mockito.Mockito.reset
[5] https://www.toptal.com/java/a-guide-to-everyday-mockito
[6] https://www.jrebel.com/blog/mock-unit-testing-with-mockito
[7] https://stackoverflow.com/questions/34412106/appropriate-use-of-mockito-reset
[8] https://groups.google.com/g/mockito/c/_vxG33tlzl8
[9] https://softwareengineering.stackexchange.com/questions/188299/is-this-an-appropriate-use-of-mockitos-reset-method
[10] https://stackoverflow.com/questions/18164123/how-to-clean-up-mocks-in-spring-tests-when-using-mockito