The XUnit family of testing tools have their origin in Kent Beck's seedwork built in Smalltalk. JUnit's first version was written by Kent and Erich Gamma on a flight to OOPSLA 97.| martinfowler.com
Integration tests see if independently developed units of software work correctly when connected. Traditionally broad they are now better narrowly scoped.| martinfowler.com
[This fragment is available in an audio version.]| ongoing by Tim Bray
Test Double is generic term for fakes, mocks, stubs, dummies and spies.| martinfowler.com
Unit Tests are focused on small parts of a code-base, defined in regular programming tools, and fast. There is disagreement on whether units should be solitary or sociable.| martinfowler.com
Write most of your tests at a low level (unit tests) with a few broad-stack tests, eg via UI. UI tests tend to be fragile and slow.| martinfowler.com
Explaining the difference between Mock Objects and Stubs (together with other forms of Test Double). Also the difference between classical and mockist styles of unit testing.| martinfowler.com