Kent Beck created the first unit testing framework called SUnit, to test Smalltalk software, in the 90’s. XP eXtreme Programming methodology and TDD Test-Driven Development approach were borning together with SUnit.
Here is the link of SUnit history: https://web.archive.org/web/20150315073817/http://www.xprogramming.com/testfram.htm
Backup here:
You can watch Kent Beck’s talk on this here:
Dionatan Moura 