l1: add EthSubscriber test

l1/l1_test.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"errors"
 	"math/big"
+	"net"
+	"net/http"
 	"testing"
 	"time"
 
@@ -15,6 +17,8 @@ import (
 	"github.com/NethermindEth/juno/l1/contract"
 	"github.com/NethermindEth/juno/mocks"
 	"github.com/NethermindEth/juno/utils"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/rpc"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/mock/gomock"
 )
@@ -154,3 +158,63 @@ func TestEventListener(t *testing.T) {
 		StateRoot: new(felt.Felt),
 	}, got)
 }
+
+func newTestL1Client(service service) *rpc.Server {
+	server := rpc.NewServer()
+	if err := server.RegisterName("eth", service); err != nil {
+		panic(err)
+	}
+	return server
+}
+
+type service interface {
+	GetBlockByNumber(ctx context.Context, number string, fullTx bool) (interface{}, error)
+}
+
+type testService struct{}
+
+func (testService) GetBlockByNumber(ctx context.Context, number string, fullTx bool) (interface{}, error) {
+	return 100, nil
+}
+
+type testEmptyService struct{}
+
+func (testEmptyService) GetBlockByNumber(ctx context.Context, number string, fullTx bool) (interface{}, error) {
+	return nil, nil
+}
+
+func TestEthSubscriber_EmptyFinalisedHeight(t *testing.T) {
+	tc := []service{
+		testService{},
+		testEmptyService{},
+	}
+
+	for _, sv := range tc {
+		t.Run("", func(t *testing.T) {
+			startServer := func(addr string, service service) (*rpc.Server, net.Listener) {
+				srv := newTestL1Client(service)
+				l, err := net.Listen("tcp", addr)
+				if err != nil {
+					t.Fatal("can't listen:", err)
+				}
+				go func() {
+					_ = http.Serve(l, srv.WebsocketHandler([]string{"*"}))
+				}()
+				return srv, l
+			}
+
+			ctx, cancel := context.WithTimeout(context.Background(), 12*time.Second)
+			defer cancel()
+
+			server, listener := startServer("127.0.0.1:0", sv)
+			defer server.Stop()
+
+			subscriber, err := l1.NewEthSubscriber("ws://"+listener.Addr().String(), common.Address{})
+			require.NoError(t, err)
+
+			height, err := subscriber.FinalisedHeight(ctx)
+			require.Equal(t, uint64(0), height)
+			require.Error(t, err)
+		})
+	}
+}