test case for lazy evaluation in the abstract syntax

testsuite/runtime/eval/lazy.gf

@@ -0,0 +1,15 @@
+abstract lazy = {
+
+cat Nat ;
+data zero : Nat ;
+     succ : Nat -> Nat ;
+
+fun infinity : Nat ;
+def infinity = succ infinity ;
+
+fun min : Nat -> Nat -> Nat ;
+def min zero     _        = zero ;
+    min _        zero     = zero ;
+    min (succ x) (succ y) = succ (min x y) ;
+
+}