[#165] Support streaming listing

Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>

api/layer/tree_mock.go

@@ -3,6 +3,7 @@ package layer
 import (
 	"context"
 	"fmt"
+	"io"
 	"sort"
 	"strings"
 
@@ -10,6 +11,21 @@ import (
 	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
 )
 
+type LatestVersionsByPrefixStreamMock struct {
+	result []*data.NodeVersion
+	offset int
+}
+
+func (s *LatestVersionsByPrefixStreamMock) Next(context.Context) (*data.NodeVersion, error) {
+	if s.offset > len(s.result)-1 {
+		return nil, io.EOF
+	}
+
+	res := s.result[s.offset]
+	s.offset++
+	return res, nil
+}
+
 type TreeServiceMock struct {
 	settings   map[string]*data.BucketSettings
 	versions   map[string]map[string][]*data.NodeVersion
@@ -196,6 +212,33 @@ func (t *TreeServiceMock) GetLatestVersionsByPrefix(_ context.Context, bktInfo *
 	return result, nil
 }
 
+func (t *TreeServiceMock) GetLatestVersionsByPrefixStream(ctx context.Context, bktInfo *data.BucketInfo, prefix string) (LatestVersionsByPrefixStream, error) {
+	cnrVersionsMap, ok := t.versions[bktInfo.CID.EncodeToString()]
+	if !ok {
+		return nil, ErrNodeNotFound
+	}
+
+	var result []*data.NodeVersion
+
+	for key, versions := range cnrVersionsMap {
+		if !strings.HasPrefix(key, prefix) {
+			continue
+		}
+
+		sort.Slice(versions, func(i, j int) bool {
+			return versions[i].ID < versions[j].ID
+		})
+
+		if len(versions) != 0 {
+			result = append(result, versions[len(versions)-1])
+		}
+	}
+
+	return &LatestVersionsByPrefixStreamMock{
+		result: result,
+	}, nil
+}
+
 func (t *TreeServiceMock) GetUnversioned(_ context.Context, bktInfo *data.BucketInfo, objectName string) (*data.NodeVersion, error) {
 	cnrVersionsMap, ok := t.versions[bktInfo.CID.EncodeToString()]
 	if !ok {