@@ 1,22 1,27 @@ 
 #!/usr/bin/env bash
 # -*- wisp -*-
-guile -L $(dirname $(realpath "$0"))) -c '(import (language wisp spec))'
-exec -a "$0" guile -L $(dirname $(realpath "$0"))) --language=wisp -x .w -e '(d6)' -c '' "$@"
+guile -L $(dirname $(realpath "$0")) -c '(import (language wisp spec))'
+exec -a "$0" guile -L $(dirname $(realpath "$0")) --language=wisp -x .w -e '(d6)' -c '' "$@"
 ; !#
 
 define-module : d6
    . #:export : roll check compete main
 
 use-modules : srfi srfi-1
+    doctests
 
 ; basic d6 rules, implemented in guile
 
 define : replace-all vals replacements
     . "replace elements in vals that match the car in
     replacements by the cdr, in order."
+    ##
+        tests
+            test-equal '(-5 -3 -1 -10 4 6)
+                replace-all '(-5 -3 -1 2 4 6) '((2 . -10))
     define : replace val
         if : equal? val (caar replacements)
-           cadr replacements
+           cdar replacements
            . val
     cond
         : null? replacements

          
@@ 72,7 77,13 @@ define* : compete skill1 skill2 effect-t
         values : >= result1 result2
                  floor/ {result1 - result2} effect-threshold
 
+define %this-module : current-module
+define : test
+  doctests-testmod %this-module
+
 define : main args
+         when : member "--test" args
+                test
          display : check 12 9 3
          newline
          newline