1 files changed, 37 insertions, 0 deletions
diff --git a/stdlib/source/test/lux/abstract/hash.lux b/stdlib/source/test/lux/abstract/hash.lux
new file mode 100644
index 000000000..d829d489e
--- /dev/null
+++ b/stdlib/source/test/lux/abstract/hash.lux
@@ -0,0 +1,37 @@
+(.module:
+  [lux #*
+   ["_" test (#+ Test)]
+   [abstract
+    [monad (#+ do)]
+    {[0 #spec]
+     [/
+      [functor
+       ["$." contravariant]]]}]
+   [data
+    [number
+     ["n" nat]
+     ["i" int]]]
+   [math
+    ["." random (#+ Random)]]]
+  {1
+   ["." /]})
+
+(def: #export test
+  Test
+  (do random.monad
+    [left random.int
+     right random.nat]
+    (<| (_.covering /._)
+        ($_ _.and
+            (_.cover [/.sum]
+                     (let [hash (/.sum i.hash n.hash)]
+                       (and (n.= (\ i.hash hash left)
+                                 (\ hash hash (#.Left left)))
+                            (n.= (\ n.hash hash right)
+                                 (\ hash hash (#.Right right))))))
+            (_.cover [/.product]
+                     (let [hash (/.product i.hash n.hash)]
+                       (n.= (n.+ (\ i.hash hash left)
+                                 (\ n.hash hash right))
+                            (\ hash hash [left right]))))
+            ))))