clean up Node resources when simulated backend is closed

eth/backend.go

@@ -101,8 +101,8 @@ type Ethereum struct {
 	shutdownTracker *shutdowncheck.ShutdownTracker // Tracks if and when the node has shutdown ungracefully
 }
 
-// New creates a new Ethereum object (including the
-// initialisation of the common Ethereum object)
+// New creates a new Ethereum object (including the initialisation of the common Ethereum object),
+// whose lifecycle will be managed by the provided node.
 func New(stack *node.Node, config *ethconfig.Config) (*Ethereum, error) {
 	// Ensure configuration values are compatible and sane
 	if config.SyncMode == downloader.LightSync {

ethclient/simulated/backend.go

@@ -62,7 +62,7 @@ type simClient struct {
 // Backend is a simulated blockchain. You can use it to test your contracts or
 // other code that interacts with the Ethereum chain.
 type Backend struct {
-	eth    *eth.Ethereum
+	node   *node.Node
 	beacon *catalyst.SimulatedBeacon
 	client simClient
 }
@@ -129,7 +129,7 @@ func newWithNode(stack *node.Node, conf *eth.Config, blockPeriod uint64) (*Backe
 		return nil, err
 	}
 	return &Backend{
-		eth:    backend,
+		node:   stack,
 		beacon: beacon,
 		client: simClient{ethclient.NewClient(stack.Attach())},
 	}, nil
@@ -142,12 +142,18 @@ func (n *Backend) Close() error {
 		n.client.Close()
 		n.client = simClient{}
 	}
+	var rerr error // return only last error if there are multiple
 	if n.beacon != nil {
-		err := n.beacon.Stop()
+		rerr = n.beacon.Stop()
 		n.beacon = nil
-		return err
 	}
-	return nil
+	if n.node != nil {
+		if err := n.node.Close(); err != nil {
+			rerr = err
+		}
+		n.node = nil
+	}
+	return rerr
 }
 
 // Commit seals a block and moves the chain forward to a new empty block.