1 files changed, 40 insertions, 0 deletions
diff --git a/stdlib/source/test/lux/type/implicit.lux b/stdlib/source/test/lux/type/implicit.lux
new file mode 100644
index 000000000..98b647bf1
--- /dev/null
+++ b/stdlib/source/test/lux/type/implicit.lux
@@ -0,0 +1,40 @@
+(.module:
+  [lux #*
+   [io]
+   [control
+    [equivalence]
+    [functor]
+    [monad (#+ Monad do)]]
+   [data
+    [bit ("bit/." equivalence)]
+    [number]
+    [collection [list]]]
+   [math
+    ["r" random]]
+   [type implicit]]
+  lux/test)
+
+(context: "Automatic structure selection"
+  (<| (times 100)
+      (do @
+        [x r.nat
+         y r.nat]
+        ($_ seq
+            (test "Can automatically select first-order structures."
+                  (let [(^open "list/.") (list.equivalence number.equivalence)]
+                    (and (bit/= (:: number.equivalence = x y)
+                                (::: = x y))
+                         (list/= (list.n/range 1 10)
+                                 (::: map inc (list.n/range 0 9)))
+                         )))
+            
+            (test "Can automatically select second-order structures."
+                  (::: =
+                    (list.n/range 1 10)
+                    (list.n/range 1 10)))
+
+            (test "Can automatically select third-order structures."
+                  (let [lln (::: map (list.n/range 1)
+                              (list.n/range 1 10))]
+                    (::: = lln lln)))
+            ))))