NOTE: El mock has moved from http://www.emacswiki.org/emacs/el-mock.el to https://github.com/rejeep/el-mock.el and its new maintainer is @rejeep.

El mock is a mocking library for Emacs.

Add this to your test-helper, for instance

(require 'el-mock)
(eval-when-compile
    (require 'cl)) ;; for el-mock

An example of a simple mock that displays "/mocked/file/name.el":

(with-mock
  (stub buffer-file-name => "/mocked/file/name.el")
  (display-message-or-buffer (buffer-file-name)))

Find the documentation at M-x describe-function RET with-mock RET and M-x describe-function RET mocklet RET.

The old documentation is at https://www.emacswiki.org/emacs/EmacsLispMock

Be sure to!

Install Cask if you haven't already.

Run the unit tests with:

$ make test