1 files changed, 52 insertions, 29 deletions
diff --git a/stdlib/source/test/lux/data/collection/stack.lux b/stdlib/source/test/lux/data/collection/stack.lux
index d203b4246..0a6fcf698 100644
--- a/stdlib/source/test/lux/data/collection/stack.lux
+++ b/stdlib/source/test/lux/data/collection/stack.lux
@@ -1,46 +1,69 @@
 (.module:
   [lux #*
+   data/text/format
+   ["_" test (#+ Test)]
    [control
-    [monad (#+ do)]]
+    [monad (#+ do)]
+    {[0 #test]
+     [/
+      ["$." equivalence]
+      ["$." functor (#+ Injection)]]}]
    [data
     ["." maybe]
-    [collection
-     ["&" stack]]]
+    [number
+     ["." nat]]]
    [math
     ["r" random]]]
-  lux/test)
+  {1
+   ["." /]})
+
+(def: (injection value)
+  (Injection /.Stack)
+  (/.push value /.empty))
 
 (def: gen-nat
   (r.Random Nat)
   (|> r.nat
       (:: r.monad map (n/% 100))))
 
-(context: "Stacks"
-  (<| (times 100)
-      (do @
+(def: #export test
+  Test
+  (<| (_.context (%name (name-of /.Stack)))
+      (do r.monad
         [size gen-nat
          sample (r.stack size gen-nat)
          new-top gen-nat]
-        ($_ seq
-            (test "Can query the size of a stack."
-                  (n/= size (&.size sample)))
-
-            (test "Can peek inside non-empty stacks."
-                  (case (&.peek sample)
-                    #.None     (&.empty? sample)
-                    (#.Some _) (not (&.empty? sample))))
-
-            (test "Popping empty stacks doesn't change anything.
-                   But, if they're non-empty, the top of the stack is removed."
-                  (let [sample' (&.pop sample)]
-                    (or (n/= (&.size sample) (inc (&.size sample')))
-                        (and (&.empty? sample) (&.empty? sample')))
-                    ))
-
-            (test "Pushing onto a stack always increases it by 1, adding a new value at the top."
-                  (and (is? sample
-                            (&.pop (&.push new-top sample)))
-                       (n/= (inc (&.size sample)) (&.size (&.push new-top sample)))
-                       (|> (&.push new-top sample) &.peek maybe.assume
-                           (is? new-top))))
+        ($_ _.and
+            ($equivalence.spec (/.equivalence nat.equivalence) (r.stack size r.nat))
+            ($functor.spec ..injection /.equivalence /.functor)
+            
+            (_.test "Can query the size of a stack."
+                    (n/= size (/.size sample)))
+            (_.test "Can peek inside non-empty stacks."
+                    (case (/.peek sample)
+                      #.None     (/.empty? sample)
+                      (#.Some _) (not (/.empty? sample))))
+            (_.test (format "Popping empty stacks doesn't change anything."
+                            "But, if they're non-empty, the top of the stack is removed.")
+                    (case (/.size sample)
+                      0 (case (/.pop sample)
+                          #.None
+                          (/.empty? sample)
+                          
+                          (#.Some _)
+                          false)
+                      expected (case (/.pop sample)
+                                 (#.Some sample')
+                                 (and (n/= expected (/.size sample'))
+                                      (not (/.empty? sample)))
+                                 
+                                 #.None
+                                 false)))
+            (_.test "Pushing onto a stack always increases it by 1, adding a new value at the top."
+                    (and (is? sample
+                              (|> sample (/.push new-top) /.pop maybe.assume))
+                         (n/= (inc (/.size sample))
+                              (/.size (/.push new-top sample)))
+                         (|> (/.push new-top sample) /.peek maybe.assume
+                             (is? new-top))))
             ))))