If we do TDD regularly, we can easily end up with a large test suite containing thousands of tests. This is great—it gives us a lot of confidence to boldly go in and add new features without worrying about breaking old features. However, it is crucial that we make test maintenance easy, otherwise we will soon be in a mess just managing the tests.

Tests that are not written to be maintained will soon bring about a number of headaches. Tests that are strewn all over the filesystem will make it impossible to locate specific tests. Tests that are difficult to read will be hard to understand and fix when the tests need to be changed due to changes in functionality. Long, poorly written tests will pose the same challenges that poor production quality code does. And brittle tests will ensure that even small changes will break a large number of tests.

Remember that test code is still code. And just like any production code, we must do our best to keep it readable...