The files in this directory test the teaching language implementation.

htdp.rktl
  load this file (racket -qr htdp.rktl) to run most of the tests
  $ racket -qr htdp.rktl
  
htdp-image.rktl
  load this file in gracket to run the htdp/image tests
  $ gracket -qr htdp-image.rktl 

See beginner.rktl for more.