diff --git a/merge-sort.rkt b/merge-sort.rkt
index 6b1f0a1..ae159f0 100644
--- a/merge-sort.rkt
+++ b/merge-sort.rkt
@@ -44,4 +44,10 @@
                            [(empty? lst) lst]
                            [(empty? (rest lst)) lst]
                            [else (merge (merge-sort (upper-half lst)) (merge-sort (lower-half lst)))]
-                           ))
\ No newline at end of file
+                           ))
+
+(check-expect (merge-sort empty) empty)
+(check-expect (merge-sort (list 4)) (list 4))
+(check-expect (merge-sort (list 7 3)) (list 3 7))
+(check-expect (merge-sort (list 1 2 3)) (list 1 2 3))
+(check-expect (merge-sort (list 6 6 6)) (list 6 6 6))
\ No newline at end of file