From f35ca5e1f62de5944418cf294444e4fc4371c4a8 Mon Sep 17 00:00:00 2001
From: Ferran Borreguero <ferran.borreguero@gmail.com>
Date: Mon, 5 Jan 2026 16:40:29 +0100
Subject: [PATCH] Fix prefund L2 addresses

---
 playground/artifacts.go       | 10 +++++++++-
 playground/artifacts_test.go  | 18 ++++++++++++++++++
 playground/components_test.go | 14 +++++++++++++-
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/playground/artifacts.go b/playground/artifacts.go
index 6105587a..a622325b 100644
--- a/playground/artifacts.go
+++ b/playground/artifacts.go
@@ -257,7 +257,7 @@ func (b *ArtifactsBuilder) Build(out *output) error {
 		// override l2 genesis, make the timestamp start 2 seconds after the L1 genesis
 		input := map[string]interface{}{
 			"timestamp": hexutil.Uint64(opTimestamp).String(),
-			"allocs":    allocs,
+			"alloc":     allocs,
 		}
 		if forkTime != nil {
 			// We need to enable prague on the EL to enable the engine v4 calls
@@ -422,6 +422,14 @@ func NewOutput(dst string) (*output, error) {
 	return out, nil
 }
 
+func (o *output) Read(path string) (string, error) {
+	data, err := os.ReadFile(filepath.Join(o.dst, path))
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
+}
+
 func (o *output) AbsoluteDstPath() (string, error) {
 	return filepath.Abs(o.dst)
 }
diff --git a/playground/artifacts_test.go b/playground/artifacts_test.go
index 083e66de..a67b1f50 100644
--- a/playground/artifacts_test.go
+++ b/playground/artifacts_test.go
@@ -1,8 +1,12 @@
 package playground
 
 import (
+	"encoding/json"
 	"os"
 	"testing"
+
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/stretchr/testify/require"
 )
 
 func TestEnodeGeneration(t *testing.T) {
@@ -17,6 +21,20 @@ func TestEnodeGeneration(t *testing.T) {
 	}
 }
 
+func TestL2PrefundedAccounts(t *testing.T) {
+	o := newTestOutput(t)
+
+	b := NewArtifactsBuilder()
+	require.NoError(t, b.Build(o))
+
+	genesisRaw, err := o.Read("l2-genesis.json")
+	require.NoError(t, err)
+
+	var genesis core.Genesis
+	require.NoError(t, json.Unmarshal([]byte(genesisRaw), &genesis))
+	require.Len(t, genesis.Alloc, 10)
+}
+
 func newTestOutput(t *testing.T) *output {
 	dir, err := os.MkdirTemp("/tmp", "test-output")
 	if err != nil {
diff --git a/playground/components_test.go b/playground/components_test.go
index df2b6567..ef77c032 100644
--- a/playground/components_test.go
+++ b/playground/components_test.go
@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"math/big"
 	"math/rand"
 	"net/http"
 	"os"
@@ -14,6 +15,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/ethclient"
 	"github.com/ethereum/go-ethereum/rpc"
 	"github.com/stretchr/testify/require"
@@ -23,7 +25,17 @@ func TestRecipeOpstackSimple(t *testing.T) {
 	tt := newTestFramework(t)
 	defer tt.Close()
 
-	tt.test(&OpRecipe{}, nil)
+	m := tt.test(&OpRecipe{}, nil)
+
+	httpPort := m.MustGetService("op-geth").MustGetPort("http")
+	client, err := ethclient.Dial(fmt.Sprintf("http://localhost:%d", httpPort.HostPort))
+	require.NoError(t, err)
+
+	// validate that the default addresses are prefunded
+	knownAddress := common.HexToAddress("0xf49Fd6e51aad88F6F4ce6aB8827279cffFb92266")
+	balance, err := client.BalanceAt(context.Background(), knownAddress, nil)
+	require.NoError(t, err)
+	require.NotEqual(t, balance, big.NewInt(0))
 }
 
 func TestRecipeOpstackExternalBuilder(t *testing.T) {