Add test for exercise 2-23

Author: ramsayleung

chapter2/exercise2-23.rkt

@@ -0,0 +1,15 @@
+#lang racket
+(define (for-each proc items)
+  (let ((a (map proc items)))
+    (= 1 1)))
+
+(module+ test
+  (require rackunit)
+
+  (test-case "Test for for-each"
+             ;; 57
+             ;; 321
+             ;; 88
+             (check-equal? (with-output-to-string (lambda () (for-each (lambda (x) (display x) (newline)) (list 57 321 88)))) "57\n321\n88\n")
+             )
+  )