Is it possible to test a specific part of a method when writing a unit test?

In the traditional understanding, unit testing involves testing a single method or function as a unit. Testing "a specific part of a method" is not directly supported, as a method is an atomic unit of code.

However, if a method is too large and complex, it is recommended to split it into several smaller methods or functions. Then, you can write separate tests for each of them.

If you need to test internal logic without changing the structure, you can use techniques such as:

• Using mock objects for dependencies to isolate part of the logic.
• Making internal methods package-private or protected and testing them directly (although this is a controversial practice).

In conclusion: it is better to refactor the code so that each part of the logic is in a separate method that can be tested independently.