added test

x/ccv/provider/keeper/keeper.go

@@ -1155,14 +1155,10 @@ func (k Keeper) SetTopN(
 func (k Keeper) GetTopN(
 	ctx sdk.Context,
 	chainID string,
-) (uint32, bool) {
+) uint32 {
 	store := ctx.KVStore(k.storeKey)
 	buf := store.Get(types.TopNKey(chainID))
-	if buf == nil {
-		return 0, false
-	} else {
-	}
-	return binary.BigEndian.Uint32(buf), true
+	return binary.BigEndian.Uint32(buf)
 }
 
 // IsTopN returns true if chain with `chainID` is a Top N chain (i.e., enforces at least one validator to validate chain `chainID`)

x/ccv/provider/keeper/keeper_test.go

@@ -628,3 +628,22 @@ func TestGetAllProposedConsumerChainIDs(t *testing.T) {
 		}
 	}
 }
+
+// TestTopN tests `SetTopN`, `GetTopN`, `IsTopN`, and `IsOptIn` methods
+func TestTopN(t *testing.T) {
+	providerKeeper, ctx, ctrl, _ := testkeeper.GetProviderKeeperAndCtx(t, testkeeper.NewInMemKeeperParams(t))
+	defer ctrl.Finish()
+
+	providerKeeper.SetTopN(ctx, "TopNChainID1", 50)
+	require.Equal(t, uint32(50), providerKeeper.GetTopN(ctx, "TopNChainID1"))
+	require.True(t, providerKeeper.IsTopN(ctx, "TopNChainID1"))
+	require.False(t, providerKeeper.IsOptIn(ctx, "TopNChainID1"))
+
+	providerKeeper.SetTopN(ctx, "TopNChainID2", 100)
+	require.Equal(t, uint32(100), providerKeeper.GetTopN(ctx, "TopNChainID2"))
+
+	providerKeeper.SetTopN(ctx, "OptInChain", 0)
+	require.Equal(t, uint32(0), providerKeeper.GetTopN(ctx, "OptInChain"))
+	require.False(t, providerKeeper.IsTopN(ctx, "OptInChain"))
+	require.True(t, providerKeeper.IsOptIn(ctx, "OptInChain"))
+}

x/ccv/provider/keeper/proposal.go

@@ -36,13 +36,6 @@ func (k Keeper) HandleConsumerAdditionProposal(ctx sdk.Context, p *types.Consume
 		return err
 	}
 
-	// you should not be able
-	if _, found := k.GetTopN(ctx, p.ChainId); found {
-		return errorsmod.Wrap(types.ErrDuplicateConsumerChain,
-			fmt.Sprint("cannot add a chain "))
-	}
-	k.SetTopN(ctx, p.ChainId, p.Top_N)
-
 	k.SetPendingConsumerAdditionProp(ctx, p)
 
 	k.Logger(ctx).Info("consumer addition proposal enqueued",
@@ -372,6 +365,7 @@ func (k Keeper) BeginBlockInit(ctx sdk.Context) {
 			ctx.Logger().Info("consumer client could not be created: %w", err)
 			continue
 		}
+		k.SetTopN(ctx, prop.ChainId, prop.Top_N)
 		// The cached context is created with a new EventManager so we merge the event
 		// into the original context
 		ctx.EventManager().EmitEvents(cachedCtx.EventManager().Events())