2 files changed, 33 insertions, 1 deletions
diff --git a/test/Distance.hs b/test/Distance.hs
new file mode 100644
index 0000000..a59b401
--- /dev/null
+++ b/test/Distance.hs
@@ -0,0 +1,30 @@
+module Distance
+  ( distanceTests
+  )
+where
+
+import Hedgehog (Property, (===))
+import qualified Hedgehog as Hog
+import qualified Hedgehog.Gen as Hog
+import qualified Hedgehog.Range as Hog
+import Verismith.Verilog.Distance
+import Test.Tasty
+import Test.Tasty.Hedgehog
+
+distanceLess :: Property
+distanceLess = Hog.property $ do
+  x <- Hog.forAll (Hog.list (Hog.linear 0 15) Hog.alpha)
+  y <- Hog.forAll (Hog.list (Hog.linear 0 15) Hog.alpha)
+  Hog.assert $ udistance x y <= distance x y
+
+distanceEq :: Property
+distanceEq = Hog.property $ do
+  x <- Hog.forAll (Hog.list (Hog.linear 0 15) Hog.alpha)
+  distance x x === 0
+  udistance x x === 0
+
+distanceTests :: TestTree
+distanceTests = testGroup "Distance tests"
+  [ testProperty "Unordered distance <= distance" distanceLess
+  , testProperty "distance x x === 0" distanceEq
+  ]
diff --git a/test/Property.hs b/test/Property.hs
index ddbef0d..2d5dcc1 100644
--- a/test/Property.hs
+++ b/test/Property.hs
@@ -13,6 +13,7 @@ where
 import Data.Either (either, isRight)
 import qualified Data.Graph.Inductive as G
 import Data.Text (Text)
+import Distance (distanceTests)
 import Hedgehog ((===), Gen, Property)
 import qualified Hedgehog as Hog
 import qualified Hedgehog.Gen as Hog
@@ -47,5 +48,6 @@ propertyTests =
   testGroup
     "Property Tests"
     [ testProperty "acyclic graph generation check" acyclicGraph,
-      parserTests
+      parserTests,
+      distanceTests
     ]