C. Keith Ray

C. Keith Ray is developing software for Sizeography and Upstart Technology. He writes code for multiple platforms and languages, including iOS® and Macintosh®.
Go to Sizeography and Upstart Technology to join our mailing lists and see more about our products. Keith's Résumé (pdf)

Wednesday, May 1, 2013

The Purpose of Unit Tests Is Not Recreating the Entire Running Environment

One of the "Aha!" experiences/epiphanies of a programmer I was working with, was the realization that a unit test only needs to test a "unit". He had been setting up real-life data, when a little "fake" data would verify the desired behavior.

Unit testing also makes the code more robust, because side-effects that might not be seen in a system test, can be found by unit tests exercising all the edge-cases for each function or behavior being tested—particularly testing situations that are hard to replicate in the real system.