Ensure sane ordering of CIDRs with equal masks with a new property.

[hath.git] / src / Cidr.hs

diff --git a/src/Cidr.hs b/src/Cidr.hs
index d7f624654743f24f6c3ac4a85939c56159e69e1d..007e94b9425ae819e3c624ae4765bdf3017d3a42 100644 (file)
--- a/src/Cidr.hs
+++ b/src/Cidr.hs
@@ -23,12 +23,13 @@ import Data.List (nub)
 import Data.List.Split (splitOneOf)
 import Data.Maybe (catMaybes, mapMaybe)
 
-import Test.Tasty ( TestTree, testGroup )
+import Test.Tasty ( TestTree, localOption, testGroup )
 import Test.Tasty.HUnit ( (@?=), testCase )
 import Test.Tasty.QuickCheck (
   Arbitrary( arbitrary ),
   Gen,
   Property,
+  QuickCheckTests( QuickCheckTests ),
   (==>),
   testProperty )
 import Text.Read (readMaybe)
@@ -304,8 +305,10 @@ cidr_properties =
       prop_contains_proper_antisymmetric,
       prop_normalize_idempotent,
       prop_normalize_preserves_equality,
+      prop_ord_instance_antisymmetric,
       prop_ord_instance_reflexive,
-      prop_ord_instance_transitive ]
+      prop_ord_instance_transitive,
+      prop_ord_uses_addr_when_masks_equal ]
 
 
 -- HUnit Tests
@@ -563,6 +566,7 @@ prop_normalize_preserves_equality =
     prop :: Cidr -> Cidr -> Bool
     prop cidr1 cidr2 = (cidr1 == cidr2) == (normalize cidr1 == normalize cidr2)
 
+
 prop_ord_instance_reflexive :: TestTree
 prop_ord_instance_reflexive =
   testProperty "The CIDR order is reflexive" prop
@@ -578,3 +582,30 @@ prop_ord_instance_transitive =
     prop :: Cidr -> Cidr -> Cidr -> Property
     prop cidr1 cidr2 cidr3 =
       (cidr1 <= cidr2 && cidr2 <= cidr3) ==> cidr1 <= cidr3
+
+-- This is how Eq is currently implemented, but it is useful to have
+-- around in case that changes. Try fewer instances of this than usual
+-- because it's a rare condition.
+prop_ord_instance_antisymmetric :: TestTree
+prop_ord_instance_antisymmetric =
+  localOption (QuickCheckTests 500) $
+    testProperty "The CIDR order is antisymmetric" prop
+  where
+    prop :: Cidr -> Cidr -> Property
+    prop cidr1 cidr2 =
+      (cidr1 <= cidr2 && cidr2 <= cidr1) ==> cidr1 == cidr2
+
+
+-- When comparing two CIDRs with the same mask, the comparison
+-- should be numeric (i.e. whatever the IPv4Address does).
+-- Of course, we have to normalize first.
+prop_ord_uses_addr_when_masks_equal :: TestTree
+prop_ord_uses_addr_when_masks_equal =
+  testProperty "The CIDR order is the IPv4Address order for equal masks" prop
+  where
+    prop :: Cidr -> Cidr -> Property
+    prop cidr1 cidr2 =
+      (mask1 == mask2) ==> (cidr1 <= cidr2) == (addr1 <= addr2)
+      where
+        (Cidr addr1 mask1) = normalize cidr1
+        (Cidr addr2 mask2) = normalize cidr2