behaviour-driven testing for Emacs Lisp packages

 Buttercup is a behavior-driven development framework for testing
 Emacs Lisp code. It allows the programmer to group related tests so
 they can share common set-up and tear-down code, and it allows the
 programmer to spy on functions to ensure they are called with the
 right arguments during testing.
 .
 The testing framework is inspired by the Jasmine JavaScript test framework.