Add lab2

lab2/llist-property-tests.rkt

@@ -0,0 +1,37 @@
+#lang racket
+
+(require rackunit)
+(require rackcheck)
+
+(require "llist.rkt")
+
+
+(define-property llist->list-is-inverse-of-list->llist
+  ([xs (gen:list gen:natural)])
+  (check-equal? (llist->list (list->llist xs)) xs))
+
+(define-property llist-append-associative
+  ([as (gen:list gen:natural)]
+   [bs (gen:list gen:natural)]
+   [cs (gen:list gen:natural)])
+  (let ([a (list->llist as)]
+        [b (list->llist bs)]
+        [c (list->llist cs)])
+    (check-equal?
+      (llist->list (llist-append a (llist-append b c)))
+      (llist->list (llist-append (llist-append a b) c)))))
+
+(define-property llist-null-is-neutral-for-append
+  ([xs (gen:list gen:natural)])
+  (let ([x (list->llist xs)])
+    (check-equal?
+      (llist->list (llist-append llist-null x))
+      xs)
+
+    (check-equal?
+      (llist->list (llist-append llist-null x))
+      (llist->list (llist-append x llist-null)))))
+
+(check-property llist->list-is-inverse-of-list->llist)
+(check-property llist-append-associative)
+(check-property llist-null-is-neutral-for-append)