Add a small margin to remaining period to prevent tx to fail

also compute wait time in ETE test with some ridiculous formula taking
into account contestation period, close grace time  and slot length!

hydra-cluster/test/Test/EndToEndSpec.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE TypeApplications #-}
 {-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
 
 module Test.EndToEndSpec where
@@ -34,7 +35,9 @@ import Hydra.Cardano.Api (
   lovelaceToValue,
   mkVkAddress,
   serialiseAddress,
+  unSlotNo,
  )
+import Hydra.Chain.Direct (closeGraceTime)
 import Hydra.Crypto (deriveVerificationKey, generateSigningKey)
 import qualified Hydra.Crypto as Hydra
 import Hydra.Ledger (txId)
@@ -273,7 +276,8 @@ initAndClose tracer clusterIx node@(RunningNode _ nodeSocket) = do
       seedFromFaucet_ defaultNetworkId node bobCardanoVk 100_000_000 Fuel
       seedFromFaucet_ defaultNetworkId node carolCardanoVk 100_000_000 Fuel
 
-      let contestationPeriod = 10 :: Natural
+      let contestationPeriod = 2
+
       send n1 $ input "Init" ["contestationPeriod" .= contestationPeriod]
       waitFor tracer 10 [n1, n2, n3] $
         output "ReadyToCommit" ["parties" .= Set.fromList [alice, bob, carol]]
@@ -342,8 +346,8 @@ initAndClose tracer clusterIx node@(RunningNode _ nodeSocket) = do
         guard $ snapshotNumber == toJSON expectedSnapshotNumber
 
       -- NOTE: We expect the head to be finalized after the contestation period
-      -- and some three secs later
-      waitFor tracer (contestationPeriod + 3) [n1] $
+      -- and some three secs later, plus the closeGraceTime * slotLength
+      waitFor tracer (truncate $ contestationPeriod + (fromIntegral @_ @Double (unSlotNo closeGraceTime) * 0.1) + 3) [n1] $
         output "HeadIsFinalized" ["utxo" .= newUTxO]
 
       case fromJSON $ toJSON newUTxO of

hydra-node/src/Hydra/Chain/Direct.hs

@@ -439,8 +439,8 @@ chainSyncHandler tracer callback headState =
         -- transformation into an `OnChainTx`
         let event = case (onChainTx, reifyState nextState) of
               (OnCloseTx{snapshotNumber}, TkClosed) ->
-                let remainingDiffTime = diffUTCTime (posixToUTCTime $ getContestationDeadline nextState) now
-                 in OnCloseTx{snapshotNumber, remainingContestationPeriod = remainingDiffTime}
+                let remainingTimeWithBuffer = 1 + diffUTCTime (posixToUTCTime $ getContestationDeadline nextState) now
+                 in OnCloseTx{snapshotNumber, remainingContestationPeriod = remainingTimeWithBuffer}
               _ -> onChainTx
         pure $ event : observed
       Nothing ->