JUnit

At this level, individuals understand the basic purpose of JUnit and recognize its importance in software development. They are familiar with the structure of a JUnit test but may not yet be comfortable writing their own tests.

Novices can write simple JUnit tests and use assertions to check for expected results. They understand the lifecycle of a JUnit test and can run tests using an IDE or build tool. However, they may still need guidance when dealing with more complex testing scenarios.

Intermediate users can write more complex tests, including parameterized tests and tests that handle exceptions. They know how to use setup and teardown methods, and can use matchers for more complex assertions. They are also comfortable grouping tests using the @TestSuite annotation.

Advanced users can write tests for asynchronous code and use mock objects and stubs with frameworks like Mockito. They can organize tests into categories and run tests in a specific order. They are also capable of integrating JUnit tests with continuous integration tools.

Experts can design and write comprehensive test suites for large applications. They can optimize test performance and execution time, implement custom runners and rules, and extend JUnit with custom assertions and matchers. They are adept at troubleshooting complex test failures and improving test reliability.