accounts/abi/bind/backends: fix bugs, add basic test

accounts/abi/bind/backends/newsim.go

@@ -1,10 +1,15 @@
 package backends
 
 import (
+	"context"
+	"os"
+	"path/filepath"
+
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/eth/catalyst"
+	"github.com/ethereum/go-ethereum/eth/downloader"
 	"github.com/ethereum/go-ethereum/eth/ethconfig"
 	"github.com/ethereum/go-ethereum/ethclient"
 	"github.com/ethereum/go-ethereum/node"
@@ -19,36 +24,48 @@ type NewSim struct {
 }
 
 func NewNewSim(alloc core.GenesisAlloc) (*NewSim, error) {
+	// Setup the node object
+	nodeConf := &node.DefaultConfig
+	nodeConf.IPCPath = "geth.ipc"
+	nodeConf.DataDir = filepath.Join(os.TempDir(), "simulated-geth")
+	stack, err := node.New(nodeConf)
+	if err != nil {
+		return nil, err
+	}
+
+	// Setup ethereum
 	genesis := core.Genesis{
-		Config:   params.AllEthashProtocolChanges,
-		GasLimit: 0,
+		Config:   params.AllDevChainProtocolChanges,
+		GasLimit: 30_000_000,
 		Alloc:    alloc,
 	}
 	conf := &ethconfig.Defaults
 	conf.Genesis = &genesis
-
-	stack, err := node.New(&node.DefaultConfig)
-	if err != nil {
-		return nil, err
-	}
+	conf.SyncMode = downloader.FullSync
 
 	backend, err := eth.New(stack, conf)
 	if err != nil {
 		return nil, err
 	}
 
+	// Start the node
+	if err := stack.Start(); err != nil {
+		return nil, err
+	}
+
+	// Set up the simulated beacon
 	beacon, err := catalyst.NewSimulatedBeacon(12, backend)
 	if err != nil {
 		return nil, err
 	}
 
-	client, err := ethclient.Dial(stack.IPCEndpoint())
-	if err != nil {
+	// Reorg our chain back to genesis
+	if err := beacon.Fork(context.Background(), backend.BlockChain().GetCanonicalHash(0)); err != nil {
 		return nil, err
 	}
 
 	return &NewSim{
 		SimulatedBeacon: beacon,
-		Client:          client,
+		Client:          ethclient.NewClient(stack.Attach()),
 	}, nil
 }

accounts/abi/bind/backends/newsim_test.go

@@ -0,0 +1,32 @@
+package backends
+
+import (
+	"context"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/core"
+)
+
+func TestNewSim(t *testing.T) {
+	genAlloc := make(core.GenesisAlloc)
+	newSim, err := NewNewSim(genAlloc)
+	if err != nil {
+		t.Fatal(err)
+	}
+	num, err := newSim.Client.BlockNumber(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if num != 0 {
+		t.Fatalf("expected 0 got %v", num)
+	}
+	// Create a block
+	newSim.Commit()
+	num, err = newSim.Client.BlockNumber(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if num != 1 {
+		t.Fatalf("expected 1 got %v", num)
+	}
+}