Devise a comprehensive testing strategy

You should devise a testing strategy that will cover most of the things that can go wrong. 

Insofar as possible:

• You should test every method independently of other methods
  • To make certain that each method behaves correctly before combining it with other methods.

If you aren't completely satisfied that a method behaves correctly:

Don't go forward with that method until you are able to resolve any unanswered questions about the behavior.