added directory for tests expected to fail

collects/2htdp/tests-failed/key-error.rkt

@@ -0,0 +1,20 @@
+#lang racket
+
+;; ---------------------------------------------------------------------------------------------------
+;; the error message should refer to the 'on-tick handler, not the lambda in the clause 
+
+(require 2htdp/universe)
+(require 2htdp/image)
+
+(define (main)
+  (big-bang 0
+            (on-tick (lambda (w) "3"))
+            (to-draw (lambda (w) (circle 10 'solid 'red)))
+            (check-with number?)))
+
+(with-handlers ((exn:fail? (lambda (x) 
+                             (define msg (exn-message x))
+                             (define hdl (regexp-match "check-with: (.*) returned" msg))
+                             (unless (and hdl (cons? (regexp-match "on-tick" (second hdl))))
+                               (error 'test "expected: \"on-tick\", actual: ~e" (second hdl))))))
+  (main))