Racket test pathing

foo.rkt

#!/usr/bin/env racket
#lang racket/gui

(define frame
  (new frame%
       [label "foo"]
       [height 30]
       [width 300]))

(define msg
  (new message%
       [parent frame]
       [label (format "exists? img/: ~a" (directory-exists? "img/"))]))

(define msg-exec
  (new message%
       [parent frame]
       [label (format "exec-file: ~a" (find-system-path 'exec-file))]))

(define msg-run
  (new message%
       [parent frame]
       [label (format "run-file: ~a" (find-system-path 'run-file))]))

(define msg-cwd
  (new message%
       [parent frame]
       [label (format "current-directory: ~a" (current-directory))]))

(send frame show #t)