CODEWITHSUNDEEP
javaunit-testingmockingmockito
Atul
Atul

Reputation: 1774

What are the best practices for writing unit tests with Mock frameworks

I am new to mocking and I have goggled a lot for the best practices but till now I couldn't find any satisfying resource so I thought of putting in SO.

I have tried few test cases and had following doubts:

  1. Do you write a separate unit test for each method (public private etc) and mock other methods calls that's being invoked inside this method or you test only public method?

  2. Is it okay to verify the invocation of stubbed method at the end when testing a method that returns nothing e.g DB insertion?

Please add other practices also that are must to know.

Upvotes: 1

Views: 1381

Answers (1)

jmkgreen
jmkgreen

Reputation: 1643

There are many levels of testing. Unit testing is of a finer granularity to integration testing which you should research separately. Regrettably this is still quite a young area of the software engineering industry and as a result the terminology is being intermixed in ways not intended.

For unit testing you should write tests that determine if the behaviour of the class meets expectations. Once you have all such tests you should find any private methods are also tested as a consequence so no need to test private methods directly. If you only test behaviour, you should find your tests never need to change although the class under test may over time - you may of course need to increase the number of tests to compensate just never change the existing tests.

Each class, in a good design, should have minimal use of other classes (collaborators). Those collaborators that get mocked are often implementing infrastructure such as database access. Be wary of testing collaboration as this is more closely associated with a larger system test - mocking collaborators gives your unit test knowledge not only of how it behaves but also how it operates which is a different subject matter.

Sorry to be vague but you are embarking on a large topic and I wanted to be brief.

Upvotes: 1

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