3 files changed, 60 insertions, 3 deletions
diff --git a/stdlib/source/test/lux/debug.lux b/stdlib/source/test/lux/debug.lux
index 17a0a1a31..bf54deb21 100644
--- a/stdlib/source/test/lux/debug.lux
+++ b/stdlib/source/test/lux/debug.lux
@@ -295,7 +295,9 @@
                          output <body>
                          _ (io.run! (sys::stdout old))]
                      [(io/StringIO::getvalue buffer)
-                      output]))]))
+                      output])
+          @.lua [""
+                 <body>])]))
 
 (def .public test
   Test
@@ -330,7 +332,8 @@
                      /.inspection)
                  true))
              (_.coverage [/.log!]
-               (let [[actual_message _] (with_out (/.log! expected_message))]
+               (let [[actual_message _] (with_out
+                                          (/.log! expected_message))]
                  (text#= (format expected_message text.\n)
                          actual_message)))
              ))))
diff --git a/stdlib/source/test/lux/math.lux b/stdlib/source/test/lux/math.lux
index db993c324..6cee94642 100644
--- a/stdlib/source/test/lux/math.lux
+++ b/stdlib/source/test/lux/math.lux
@@ -29,7 +29,9 @@
   ["[1][0]" random]
   ["[1][0]" logic
    ["[1]/[0]" continuous]
-   ["[1]/[0]" fuzzy]]])
+   ["[1]/[0]" fuzzy]]
+  ["[1][0]" arithmetic
+   ["[1]/[0]" saturation]]])
 
 (def ratio/0
   Ratio
@@ -145,4 +147,5 @@
                /random.test
                /logic/continuous.test
                /logic/fuzzy.test
+               /arithmetic/saturation.test
                ))))
diff --git a/stdlib/source/test/lux/math/arithmetic/saturation.lux b/stdlib/source/test/lux/math/arithmetic/saturation.lux
new file mode 100644
index 000000000..3ef3adb94
--- /dev/null
+++ b/stdlib/source/test/lux/math/arithmetic/saturation.lux
@@ -0,0 +1,51 @@
+(.require
+ [library
+  [lux (.except)
+   [abstract
+    [monad (.only do)]]
+   [math
+    ["[0]" random (.only Random)]
+    [number
+     ["n" nat]]]
+   [test
+    ["_" property (.only Test)]]]]
+ [\\library
+  ["[0]" /]])
+
+(def (within_boundaries? [min max] it)
+  (-> [Nat Nat] Nat
+      Bit)
+  (and (n.<= max it)
+       (n.>= min it)))
+
+(def .public test
+  Test
+  (<| (_.covering /._)
+      (do [! random.monad]
+        [left random.nat
+         right random.nat
+         .let [max (n.max left right)
+               min (n.min left right)]
+
+         parameter (random.only (n.> 0) random.nat)
+         subject random.nat])
+      (all _.and
+           (_.coverage [/.arithmetic]
+             (let [boundaries_are_respected!
+                   (let [(open "/#[0]") (/.arithmetic n.order [min max] n.arithmetic)]
+                     (and (within_boundaries? [min max] (/#+ parameter subject))
+                          (within_boundaries? [min max] (/#- parameter subject))
+                          (within_boundaries? [min max] (/#* parameter subject))
+                          (within_boundaries? [min max] (/#/ parameter subject))
+                          (within_boundaries? [min max] (/#% parameter subject))))
+
+                   the_order_of_the_boundaries_does_not_matter!
+                   (let [(open "/#[0]") (/.arithmetic n.order [max min] n.arithmetic)]
+                     (and (within_boundaries? [min max] (/#+ parameter subject))
+                          (within_boundaries? [min max] (/#- parameter subject))
+                          (within_boundaries? [min max] (/#* parameter subject))
+                          (within_boundaries? [min max] (/#/ parameter subject))
+                          (within_boundaries? [min max] (/#% parameter subject))))]
+               (and boundaries_are_respected!
+                    the_order_of_the_boundaries_does_not_matter!)))
+           )))