Add WIP test

pkg/storage/stores/series/series_index_gateway_store_test.go

@@ -2,12 +2,15 @@ package series
 
 import (
 	"context"
+	"log"
+	"net"
 	"testing"
 
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/grpc"
 
+	"github.com/grafana/dskit/grpcclient"
 	"github.com/grafana/loki/pkg/storage/stores/shipper/indexgateway/indexgatewaypb"
 )
 
@@ -29,3 +32,55 @@ func Test_IndexGatewayClient(t *testing.T) {
 	_, err := idx.GetSeries(context.Background(), "foo", model.Earliest, model.Latest)
 	require.NoError(t, err)
 }
+
+func Test_IndexGatewayClient_Fallback(t *testing.T) {
+	lis, err := net.Listen("tcp", "localhost:0")
+	require.NoError(t, err)
+	s := grpc.NewServer()
+
+	// register fake grpc service with missing methods
+	desc := grpc.ServiceDesc{
+		ServiceName: "indexgatewaypb.IndexGateway",
+		HandlerType: (*indexgatewaypb.IndexGatewayServer)(nil),
+		Streams: []grpc.StreamDesc{
+			{
+				StreamName:    "QueryIndex",
+				Handler:       nil,
+				ServerStreams: true,
+			},
+		},
+		Metadata: "pkg/storage/stores/shipper/indexgateway/indexgatewaypb/gateway.proto",
+	}
+	s.RegisterService(&desc, nil)
+
+	go func() {
+		if err := s.Serve(lis); err != nil {
+			log.Fatalf("Failed to serve: %v", err)
+		}
+	}()
+	defer func() {
+		s.GracefulStop()
+	}()
+
+	cfg := grpcclient.Config{
+		MaxRecvMsgSize: 1024,
+		MaxSendMsgSize: 1024,
+	}
+
+	dialOpts, err := cfg.DialOption(nil, nil)
+	require.NoError(t, err)
+
+	conn, err := grpc.Dial(lis.Addr().String(), dialOpts...)
+	require.NoError(t, err)
+	defer conn.Close()
+
+	idx := NewIndexGatewayClientStore(
+		indexgatewaypb.NewIndexGatewayClient(conn),
+		&IndexStore{
+			chunkBatchSize: 1,
+		},
+	)
+
+	_, err = idx.GetSeries(context.Background(), "foo", model.Earliest, model.Latest)
+	require.NoError(t, err)
+}