I like to think of test coverage as a grid. On the horizontal layers you have unit testing, integration testing, acceptance testing - which are tests at variou

I like to think of test coverage as a grid. On the horizontal layers you have unit testing, integration testing, acceptance testing - which are tests at various levels of abstraction throughout your code base. I then like to test the vertical slices tiers of the application - usually views, controllers, models, database etc. I like to see unit tests, integration tests, and 'acceptance tests' focusing in on each of those tiers to build confidence in the coverage of your testing. Automation is absolutely key, and getting those automated tests into your continuous build and release process is definitely worthwhile.