Unit testing can be difficult sometimes. In some cases, you need to refactor your code-under-test to make it more testable; in other cases, you need to apply some special techniques into your test code so that it can do what you want; and in the worst cases, you can%u2019t think of any such techniques nor are able to refactor the production code and thus, don%u2019t write any test at all. It%u2019s in my experience working with many teams applying unit testing that they often have troubles writing tests for the data access layer (DAL), the UI layer, and multi-threading code, mostly because they are not aware of the techniques for doing that. That is not surprisingly difficult to understand though, business logic is much more intuitive and straight-forward to be tested and every single article or book out there will have examples writing test for the business logic firstly.

Author: Buu Nguyen
Published: September 30, 2007