Add a test case for many cold keys mapping to one hot key

eras/conway/impl/testlib/Test/Cardano/Ledger/Conway/Imp/RatifySpec.hs

@@ -945,6 +945,22 @@ votingSpec =
             passNEpochs 2
             -- The same vote should now successfully ratify the proposal
             getLastEnactedCommittee `shouldReturn` SJust (GovPurposeId addCCGaid)
+          it "Many CC Cold Credentials map to the same Hot Credential act as many votes" $ do
+            hotCred NE.:| _ <- registerInitialCommittee
+            (dRep, _, _) <- setupSingleDRep . getPositive =<< arbitrary
+            Positive deposit <- arbitrary
+            gaId <- submitParameterChange SNothing $ def & ppuDRepDepositL .~ SJust (Coin deposit)
+            submitYesVote_ (CommitteeVoter hotCred) gaId
+            whenPostBootstrap $ submitYesVote_ (DRepVoter dRep) gaId
+            passNEpochs 2
+            getLastEnactedParameterChange `shouldReturn` SNothing
+            -- Make sure all committee members authorize the same hot credential that just voted:
+            committeeMembers' <- Set.toList <$> getCommitteeMembers
+            case committeeMembers' of
+              x : xs -> void $ registerCommitteeHotKeys (pure hotCred) $ x NE.:| xs
+              _ -> error "Expected an initial committee"
+            passNEpochs 2
+            getLastEnactedParameterChange `shouldReturn` SJust (GovPurposeId gaId)
 
 delayingActionsSpec ::
   forall era.