3 files changed, 54 insertions, 0 deletions
diff --git a/stdlib/source/test/lux/data/collection/list.lux b/stdlib/source/test/lux/data/collection/list.lux
index 06218dbb8..458b447e4 100644
--- a/stdlib/source/test/lux/data/collection/list.lux
+++ b/stdlib/source/test/lux/data/collection/list.lux
@@ -174,6 +174,17 @@
                                  {.#None}
                                  false))
                              (/.enumeration sample)))
+          (do !
+            [index (case size
+                     0 random.nat
+                     _ (# ! each (n.% size) random.nat))
+             .let [changed? (/#= sample (/.revised index ++ sample))
+                   same? (/#= sample (/.revised size ++ sample))]]
+            (_.cover [/.revised]
+                     (case size
+                       0 (and changed?
+                              same?)
+                       _ (not changed?))))
           ))))
 
 (def: slice
diff --git a/stdlib/source/test/lux/tool.lux b/stdlib/source/test/lux/tool.lux
index f7734328b..e2cbc50b6 100644
--- a/stdlib/source/test/lux/tool.lux
+++ b/stdlib/source/test/lux/tool.lux
@@ -5,6 +5,7 @@
  ["[0]" / "_"
   [compiler
    ["[1][0]" arity]
+   ["[1][0]" version]
    ["[1][0]" reference]
    [language
     [lux
@@ -21,6 +22,7 @@
   Test
   ($_ _.and
       /arity.test
+      /version.test
       /reference.test
       /analysis/primitive.test
       ... /syntax.test
diff --git a/stdlib/source/test/lux/tool/compiler/version.lux b/stdlib/source/test/lux/tool/compiler/version.lux
new file mode 100644
index 000000000..01fc124a1
--- /dev/null
+++ b/stdlib/source/test/lux/tool/compiler/version.lux
@@ -0,0 +1,41 @@
+(.using
+ [library
+  [lux "*"
+   ["_" test {"+" Test}]
+   [abstract
+    [monad {"+" do}]]
+   [data
+    ["[0]" bit ("[1]#[0]" equivalence)]
+    ["[0]" text ("[1]#[0]" equivalence)
+     ["%" format {"+" format}]]]
+   [math
+    ["[0]" random {"+" Random}]
+    [number
+     ["n" nat]]]]]
+ [\\library
+  ["[0]" /]])
+
+(def: .public random
+  (Random /.Version)
+  random.nat)
+
+(def: .public test
+  Test
+  (<| (_.covering /._)
+      (_.for [/.Version])
+      (do [! random.monad]
+        [this ..random
+         that ..random]
+        (`` ($_ _.and
+                (_.cover [/.format]
+                         (bit#= (n.= this that)
+                                (text#= (/.format this) (/.format that))))
+                (~~ (template [<level>]
+                      [(_.cover [<level>]
+                                (text.contains? (%.nat (<level> this))
+                                                (/.format this)))]
+
+                      [/.patch]
+                      [/.minor]
+                      [/.major]))
+                )))))