What are the best practices for mocking in Java?

What are the best practices for mocking in Java?

When mocking in Java, it's important to use a mocking framework like Mockito. Key practices include: 1. Mock only external dependencies, not the class under test. 2. Use meaningful names for mocks to clarify their purpose. 3. Keep your tests isolated and independent. 4. Verify interactions with mocks to ensure expected behavior.

Can you explain why it's important to mock external dependencies?

Mocking external dependencies is crucial because it allows you to isolate the unit of work being tested. This ensures that tests are not affected by the behavior of external systems, making them more reliable and faster.

What are some common mistakes to avoid when mocking?

Common mistakes include over-mocking, which can lead to brittle tests, and not verifying interactions, which can result in missed errors. Also, avoid mocking final classes or methods, as it can complicate your tests.

How do I choose between using mocks and stubs?

Use mocks when you need to verify interactions and behavior, while stubs are suitable for providing predefined responses without verifying interactions. The choice depends on the test's focus.