Framework for developing and using mock objects

 Mock Objects is a test-first driven framework for building
 generic software and/or unit testing frameworks. It supports:
  * A methodology for developing and using mock objects.
  * A core mock object framework. This is a library of code that
  supports the implementation of mock objects, based around a
  set of expectation classes for values and collections. There are
  also various other classes to make mock objects easier to write
  or to use.
  * A default set of mock implementations for the standard Java
  platform APIs. We have made a start on packages such as servlets, sql,
  and io.