Liam Healy - April 26th, 2006

09:56 am - Unit (regression) test in Lisp

I was looking around for a regression or unit test package for Lisp; a long time ago I used Waters' RT, but I thought maybe somebody had something newer. Indeed, I found lisp-unit from Northwestern University which is thorough, well organized and documented. Being a floating point person, I found it necessary to add one assert type, a floating point number comparison test. This works by formatting the number to a string with 12 significant digits, and comparing that with the known result. I chose 12 digits because that's enough to show double-float accuracy but not so much that inconsistencies at the machine epsilon level will trigger errors.