This morning I have been doing a lot of refactoring and adding new features to some modules I haven't looked at in about a month or more.
One of the modules has 40 tests as well as the basic sanity check ( use all modules in package, instantiate all objects and check they are objects ) that all my work code has.
When I ran 'make test' after a couple of hours of refactoring it, all the tests passed, definately a good thing.
I need to write a whole load more tests to ensure that the functionality I have added doesn't get broken at the next bug fix or feature is coded.
I still have a lot more tests to write, and it will be quite time-consuming but it will be well worth it in time saved later.