Merge pull request 'Implement test for sequential address generation' (#30) from rav001 into dev040

Reviewed-on: #30

test/Spec.hs

@@ -476,6 +476,8 @@ main = do
           property $ prop_SaplingSpendingKey s
         it "Sapling receivers are valid" $ \s ->
           property $ prop_SaplingReceiver s
+        it "Sapling receivers are not the same" $ \s ->
+          property $ prop_SaplingRecRepeated s
         it "Orchard spending keys are valid" $ \s ->
           property $ prop_OrchardSpendingKey s
         it "Orchard receivers are valid" $ \s ->
@@ -618,6 +620,11 @@ prop_SaplingReceiver s (NonNegative i) (NonNegative j) =
   genSaplingPaymentAddress (fromMaybe "" $ genSaplingSpendingKey s j) i =/=
   Nothing
 
+prop_SaplingRecRepeated :: Seed -> NonNegative Int -> Property
+prop_SaplingRecRepeated s (NonNegative i) =
+  genSaplingPaymentAddress (fromMaybe "" $ genSaplingSpendingKey s 1) i =/=
+  genSaplingPaymentAddress (fromMaybe "" $ genSaplingSpendingKey s 1) (i + 1)
+
 -- | Generators
 genOrcArgs :: Gen (CoinType, Int, Int)
 genOrcArgs = do