Extreme Programming (sometimes abbreviated as XP), is a light-weight development methodology developed by Kent Beck. There are now several books about XP.1], which supports testing with Smalltalk.)Java has JUnit.Tcl has tclunit. (Tcl's built-in tcltest framework is also eminently suitable for unit testing.)See also XotclIDE.The Portland Pattern Repository Wiki  has an extensive collection of pages on ExtremeProgramming .See http://park.ruru.ne.jp/ando/work/tclTkUnit/ for TclTkUnit , a JUnit like testing framework.TclTkUnit appears to be a dead project, software can be accessed at archive.org http://web.archive.org/web/20091009212801/http://park.ruru.ne.jp/ando/work/tclTkUnit/.