e2e/system: add test for the batcher recovering from an L2 chain rewind

op-e2e/system/da/l2_rewind_test.go

@@ -0,0 +1,48 @@
+package da
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	op_e2e "github.com/ethereum-optimism/optimism/op-e2e"
+
+	"github.com/ethereum-optimism/optimism/op-e2e/e2eutils/wait"
+	"github.com/ethereum-optimism/optimism/op-e2e/system/e2esys"
+	"github.com/stretchr/testify/require"
+)
+
+// This test verifies that the batcher can recover from a rewind of the L2 chain.
+func TestBatcherL2Rewind(t *testing.T) {
+	op_e2e.InitParallel(t)
+	cfg := e2esys.DefaultSystemConfig(t)
+	cfg.DisableProposer = true
+	sys, err := cfg.Start(t)
+	require.NoError(t, err, "Error starting up system")
+
+	l2Seq := sys.NodeClient("sequencer")
+
+	// Wait for a short safe chain to be built.
+	safeChainLength := 5
+	err = wait.ForSafeBlock(context.Background(), sys.RollupClient("sequencer"), uint64(safeChainLength))
+	require.NoError(t, err)
+
+	// rewind the L2 unsafe chain
+	result := make(map[string]interface{})
+	err = l2Seq.Client().Call(&result, "debug_setHead", "0x0")
+	require.NoError(t, err)
+	t.Log("INTERVENTION: called debugSetHead with result: ", result)
+
+	// Wait for the intervention to take effect
+	time.Sleep(time.Second * 5)
+
+	// The batcher should be able to recover from the sequencer rewind
+	require.Eventually(t, func() bool {
+		ss, err := sys.RollupClient(e2esys.RoleSeq).SyncStatus(context.Background())
+		if err == nil && ss.SafeL2.Number > uint64(safeChainLength) {
+			return true
+		}
+		t.Log("Waiting for safe head to advance", "safe head", ss.SafeL2.Number)
+		return false
+	}, time.Second*10, time.Second, "Safe head did not advance")
+}