--- /dev/null
+(require 'test-simple)
+
+(test-simple-start)
+
+(assert-t (load-file "./gcd.el")
+ "Can't load gcd.el - are you in the right directory?" )
+
+(note "degenereate cases")
+
+(assert-nil (gcd 5 -1) "using positive numbers")
+(assert-nil (gcd -4 1) "using positive numbers, switched order")
+
+(note "GCD computations")
+(assert-equal 1 (gcd 3 5) "gcd(3,5)")
+(assert-equal 8 (gcd 8 32) "gcd(8,32)")
+
+(assert-raises error (gcd "a" 32)
+ "Passing a string value should raise an error")
+
+(end-tests)