op-e2e: Add test utility to wait for balance changes

This PR adds a utility to wait for an address's balance to change. The utility checks for the balance change for two minutes, and returns the new value once it changes. It rreturns an error on timeout.

Some tests - particularly the ext-geth tests - are failing because balance changes that we expect to occur are not. My hunch is that this may be related to a race condition somewhere between the test code and op-geth, but I can't be sure. By waiting for the balance to change, we can eliminate spurious race conditions and see if this is related to some other underlying issue.

op-e2e/e2eutils/wait/waits.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"math/big"
 	"time"
 
 	"github.com/ethereum/go-ethereum"
@@ -13,6 +14,22 @@ import (
 	"github.com/ethereum/go-ethereum/ethclient"
 )
 
+func ForBalanceChange(ctx context.Context, client *ethclient.Client, address common.Address, initial *big.Int) (*big.Int, error) {
+	ctx, cancel := context.WithTimeout(ctx, 2*time.Minute)
+	defer cancel()
+
+	return AndGet[*big.Int](
+		ctx,
+		100*time.Millisecond,
+		func() (*big.Int, error) {
+			return client.BalanceAt(ctx, address, nil)
+		},
+		func(b *big.Int) bool {
+			return b.Cmp(initial) != 0
+		},
+	)
+}
+
 func ForReceiptOK(ctx context.Context, client *ethclient.Client, hash common.Hash) (*types.Receipt, error) {
 	return ForReceipt(ctx, client, hash, types.ReceiptStatusSuccessful)
 }

op-e2e/system_test.go

@@ -250,7 +250,8 @@ func runE2ESystemTest(t *testing.T, sys *System) {
 	// Confirm balance
 	ctx, cancel = context.WithTimeout(context.Background(), 15*time.Second)
 	defer cancel()
-	endBalance, err := l2Verif.BalanceAt(ctx, fromAddr, nil)
+
+	endBalance, err := wait.ForBalanceChange(ctx, l2Verif, fromAddr, startBalance)
 	require.Nil(t, err)
 
 	diff := new(big.Int)
@@ -1047,7 +1048,7 @@ func TestWithdrawals(t *testing.T) {
 	// Start L2 balance
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
 	defer cancel()
-	startBalance, err := l2Verif.BalanceAt(ctx, fromAddr, nil)
+	startBalanceBeforeDeposit, err := l2Verif.BalanceAt(ctx, fromAddr, nil)
 	require.Nil(t, err)
 
 	// Send deposit tx
@@ -1060,17 +1061,17 @@ func TestWithdrawals(t *testing.T) {
 	// Confirm L2 balance
 	ctx, cancel = context.WithTimeout(context.Background(), 1*time.Second)
 	defer cancel()
-	endBalance, err := l2Verif.BalanceAt(ctx, fromAddr, nil)
+	endBalanceAfterDeposit, err := wait.ForBalanceChange(ctx, l2Verif, fromAddr, startBalanceBeforeDeposit)
 	require.Nil(t, err)
 
 	diff := new(big.Int)
-	diff = diff.Sub(endBalance, startBalance)
+	diff = diff.Sub(endBalanceAfterDeposit, startBalanceBeforeDeposit)
 	require.Equal(t, mintAmount, diff, "Did not get expected balance change after mint")
 
 	// Start L2 balance for withdrawal
 	ctx, cancel = context.WithTimeout(context.Background(), 1*time.Second)
 	defer cancel()
-	startBalance, err = l2Seq.BalanceAt(ctx, fromAddr, nil)
+	startBalanceBeforeWithdrawal, err := l2Seq.BalanceAt(ctx, fromAddr, nil)
 	require.Nil(t, err)
 
 	withdrawAmount := big.NewInt(500_000_000_000)
@@ -1087,11 +1088,11 @@ func TestWithdrawals(t *testing.T) {
 
 	ctx, cancel = context.WithTimeout(context.Background(), 1*time.Second)
 	defer cancel()
-	endBalance, err = l2Verif.BalanceAt(ctx, fromAddr, nil)
+	endBalanceAfterWithdrawal, err := wait.ForBalanceChange(ctx, l2Seq, fromAddr, startBalanceBeforeWithdrawal)
 	require.Nil(t, err)
 
 	// Take fee into account
-	diff = new(big.Int).Sub(startBalance, endBalance)
+	diff = new(big.Int).Sub(startBalanceBeforeWithdrawal, endBalanceAfterWithdrawal)
 	fees := calcGasFees(receipt.GasUsed, tx.GasTipCap(), tx.GasFeeCap(), header.BaseFee)
 	fees = fees.Add(fees, receipt.L1Fee)
 	diff = diff.Sub(diff, fees)
@@ -1100,7 +1101,7 @@ func TestWithdrawals(t *testing.T) {
 	// Take start balance on L1
 	ctx, cancel = context.WithTimeout(context.Background(), 1*time.Second)
 	defer cancel()
-	startBalance, err = l1Client.BalanceAt(ctx, fromAddr, nil)
+	startBalanceBeforeFinalize, err := l1Client.BalanceAt(ctx, fromAddr, nil)
 	require.Nil(t, err)
 
 	proveReceipt, finalizeReceipt := ProveAndFinalizeWithdrawal(t, cfg, l1Client, sys.EthInstances["verifier"], ethPrivKey, receipt)
@@ -1108,13 +1109,13 @@ func TestWithdrawals(t *testing.T) {
 	// Verify balance after withdrawal
 	ctx, cancel = context.WithTimeout(context.Background(), 1*time.Second)
 	defer cancel()
-	endBalance, err = l1Client.BalanceAt(ctx, fromAddr, nil)
+	endBalanceAfterFinalize, err := wait.ForBalanceChange(ctx, l1Client, fromAddr, startBalanceBeforeFinalize)
 	require.Nil(t, err)
 
 	// Ensure that withdrawal - gas fees are added to the L1 balance
 	// Fun fact, the fee is greater than the withdrawal amount
 	// NOTE: The gas fees include *both* the ProveWithdrawalTransaction and FinalizeWithdrawalTransaction transactions.
-	diff = new(big.Int).Sub(endBalance, startBalance)
+	diff = new(big.Int).Sub(endBalanceAfterFinalize, startBalanceBeforeFinalize)
 	proveFee := new(big.Int).Mul(new(big.Int).SetUint64(proveReceipt.GasUsed), proveReceipt.EffectiveGasPrice)
 	finalizeFee := new(big.Int).Mul(new(big.Int).SetUint64(finalizeReceipt.GasUsed), finalizeReceipt.EffectiveGasPrice)
 	fees = new(big.Int).Add(proveFee, finalizeFee)