do you have any Best Practice for testing

Test everything that you want to work
More test methods in your TestCase than in the class you are testing
Tests should be as fine grained as possible
Tests should be independent
Should not take long to run (a few seconds)
Easy to understand and read
Make them safe
Developers must know they are not destructive
All developers must know about them
Everyone who touches the code must run the tests.
Determines how much of your code is covered by tests
If developer changes functionality, they may need to update test
Warning: you’ve changed the interface. Did you break someone else?
Even better, all tests pass AND new tests were added for new code
All tests pass all the time
Don’t allow even one test the “always fails”
Track down and fix the broken test immediately
Automate running of tests
Ex. All tests on tip revision of code get run automatically once per day with failures emailed.
Run tests on code check-in
Run tests before deployment
Have a reasonable copy of your production environment in a dev area.