Green Is Good: Keeping Our Tests Relevant
You should normally expect that all tests pass all of the time. In practice, that means that when you introduce a bug, only one or two tests fail. Isolating the problem is usually pretty easy in that environment.
Do not continue adding features when there are failing tests! Fix any test as soon as it fails, and keep all tests passing all of the time. “All green all of the time!” will keep you sane when you must change production code.
Keeping Our Tests Fast
Eclipse and other IDEs make it easy to run only the tests defined in a single test class. Some IDEs allow you to run just one unit test at a time. So one way to run your tests all the time and keep them green is to run only the ones you think you ...