Marco Castellani's Library tagged junit → View Popular

24 Jun 09

Writing tests first is a programming technique that takes practice, and lots of it. Accept the fact that you won't see miraculous results overnight. Experts say it takes a minimum of 21 days to build a positive habit and six months for it to become part of your personality. So when you feel yourself backsliding, don't despair. Just keep pressing on and pay careful attention to mental assertions you're making that could be codified in tests. Your brain will love you for it!

23 Jun 09

Notice that the result checking is now codified in the use of assertEquals() methods that automatically check whether the expected value (the first parameter) matches the actual value (the second parameter). There's no need for you to remember what the correct results should be.
Most Java IDEs have an integrated graphical runner just waiting to stroke your ego, such as this runner in Eclipse:
5 more annotations...
- As you write more tests, it doesn't cost you anything to keep them running.
- Write new code only after an automated test has failed.
  Refactor to keep the code clean.
- Writing the test first is typically easier and quicker than writing the corresponding code. The test then keeps you from wandering down rabbit holes and lets you know when you're done coding. So, before writing that next method, stop to consider what expectations you already have in mind. Assume you've already written the method, then simply write an automated test that asserts that the method works correctly.
- Now that you have a test, write just enough code to make it pass. No more, no less. Just let the test guide you rather than speculating about what you might need in the future or worrying about the next test.
- Before long you'll fall into your own test-code-refactor rhythm. Stick with it; it will serve you well.

22 Jun 09

unit tests are written to test the
fundamental building blocks of the system from the inside out.
Any class that contains
test methods should subclass the TestCase class.
3 more annotations...
- Each test runs in the context of its own fixture,
  calling setUp() before and tearDown() after
  each test method to ensure there can be no side effects among test
  runs.
- Test a little, code a little, test a little, code a little...
- Write unit tests before writing the code and only write new code
  when a test is failing.