diff --git a/dot/sync/interfaces.go b/dot/sync/interfaces.go
index f6154e8c62..8eac5c99fa 100644
--- a/dot/sync/interfaces.go
+++ b/dot/sync/interfaces.go
@@ -25,6 +25,7 @@ type BlockState interface {
 	GetBlockBody(common.Hash) (*types.Body, error)
 	GetHeader(common.Hash) (*types.Header, error)
 	HasHeader(hash common.Hash) (bool, error)
+	Range(startHash, endHash common.Hash) (hashes []common.Hash, err error)
 	RangeInMemory(start, end common.Hash) ([]common.Hash, error)
 	GetReceipt(common.Hash) ([]byte, error)
 	GetMessageQueue(common.Hash) ([]byte, error)
diff --git a/dot/sync/message.go b/dot/sync/message.go
index 2698bdf0dd..4c1ad50470 100644
--- a/dot/sync/message.go
+++ b/dot/sync/message.go
@@ -291,9 +291,9 @@ func (s *Service) handleDescendingByNumber(start, end uint,
 func (s *Service) handleChainByHash(ancestor, descendant common.Hash,
 	max uint, requestedData byte, direction network.SyncDirection) (
 	*network.BlockResponseMessage, error) {
-	subchain, err := s.blockState.RangeInMemory(ancestor, descendant)
+	subchain, err := s.blockState.Range(ancestor, descendant)
 	if err != nil {
-		return nil, fmt.Errorf("retrieving subchain: %w", err)
+		return nil, fmt.Errorf("retrieving range: %w", err)
 	}
 
 	// If the direction is descending, prune from the start.
diff --git a/dot/sync/message_test.go b/dot/sync/message_test.go
index d72aa03f22..e3ce179be2 100644
--- a/dot/sync/message_test.go
+++ b/dot/sync/message_test.go
@@ -27,7 +27,7 @@ func TestService_CreateBlockResponse(t *testing.T) {
 		want              *network.BlockResponseMessage
 		err               error
 	}{
-		"invalid block request": {
+		"invalid_block_request": {
 			blockStateBuilder: func(ctrl *gomock.Controller) BlockState {
 				mockBlockState := NewMockBlockState(ctrl)
 				mockBlockState.EXPECT().BestBlockNumber().Return(uint(1), nil)
@@ -36,7 +36,7 @@ func TestService_CreateBlockResponse(t *testing.T) {
 			args: args{req: &network.BlockRequestMessage{}},
 			err:  ErrInvalidBlockRequest,
 		},
-		"ascending request nil startHash": {
+		"ascending_request_nil_startHash": {
 			blockStateBuilder: func(ctrl *gomock.Controller) BlockState {
 				mockBlockState := NewMockBlockState(ctrl)
 				mockBlockState.EXPECT().BestBlockNumber().Return(uint(1), nil)
@@ -51,7 +51,7 @@ func TestService_CreateBlockResponse(t *testing.T) {
 				Hash: common.Hash{1, 2},
 			}}},
 		},
-		"ascending request start number higher": {
+		"ascending_request_start_number_higher": {
 			blockStateBuilder: func(ctrl *gomock.Controller) BlockState {
 				mockBlockState := NewMockBlockState(ctrl)
 				mockBlockState.EXPECT().BestBlockNumber().Return(uint(1), nil)
@@ -65,7 +65,7 @@ func TestService_CreateBlockResponse(t *testing.T) {
 			err:  errRequestStartTooHigh,
 			want: nil,
 		},
-		"descending request nil startHash": {
+		"descending_request_nil_startHash": {
 			blockStateBuilder: func(ctrl *gomock.Controller) BlockState {
 				mockBlockState := NewMockBlockState(ctrl)
 				mockBlockState.EXPECT().BestBlockNumber().Return(uint(1), nil)
@@ -77,7 +77,7 @@ func TestService_CreateBlockResponse(t *testing.T) {
 			}},
 			want: &network.BlockResponseMessage{BlockData: []*types.BlockData{}},
 		},
-		"descending request start number higher": {
+		"descending_request_start_number_higher": {
 			blockStateBuilder: func(ctrl *gomock.Controller) BlockState {
 				mockBlockState := NewMockBlockState(ctrl)
 				mockBlockState.EXPECT().BestBlockNumber().Return(uint(1), nil)
@@ -93,7 +93,7 @@ func TestService_CreateBlockResponse(t *testing.T) {
 				Hash: common.Hash{1, 2},
 			}}},
 		},
-		"ascending request startHash": {
+		"ascending_request_startHash": {
 			blockStateBuilder: func(ctrl *gomock.Controller) BlockState {
 				mockBlockState := NewMockBlockState(ctrl)
 				mockBlockState.EXPECT().GetHeader(common.Hash{}).Return(&types.Header{
@@ -103,7 +103,7 @@ func TestService_CreateBlockResponse(t *testing.T) {
 				mockBlockState.EXPECT().GetHashByNumber(uint(2)).Return(common.Hash{1, 2, 3}, nil)
 				mockBlockState.EXPECT().IsDescendantOf(common.Hash{}, common.Hash{1, 2, 3}).Return(true,
 					nil)
-				mockBlockState.EXPECT().RangeInMemory(common.Hash{}, common.Hash{1, 2, 3}).Return([]common.Hash{{1,
+				mockBlockState.EXPECT().Range(common.Hash{}, common.Hash{1, 2, 3}).Return([]common.Hash{{1,
 					2}},
 					nil)
 				return mockBlockState
@@ -116,7 +116,7 @@ func TestService_CreateBlockResponse(t *testing.T) {
 				Hash: common.Hash{1, 2},
 			}}},
 		},
-		"descending request startHash": {
+		"descending_request_startHash": {
 			blockStateBuilder: func(ctrl *gomock.Controller) BlockState {
 				mockBlockState := NewMockBlockState(ctrl)
 				mockBlockState.EXPECT().GetHeader(common.Hash{}).Return(&types.Header{
@@ -125,7 +125,7 @@ func TestService_CreateBlockResponse(t *testing.T) {
 				mockBlockState.EXPECT().GetHeaderByNumber(uint(1)).Return(&types.Header{
 					Number: 1,
 				}, nil)
-				mockBlockState.EXPECT().RangeInMemory(common.MustHexToHash(
+				mockBlockState.EXPECT().Range(common.MustHexToHash(
 					"0x6443a0b46e0412e626363028115a9f2cf963eeed526b8b33e5316f08b50d0dc3"),
 					common.Hash{}).Return([]common.Hash{{1, 2}}, nil)
 				return mockBlockState
@@ -138,7 +138,7 @@ func TestService_CreateBlockResponse(t *testing.T) {
 				Hash: common.Hash{1, 2},
 			}}},
 		},
-		"invalid direction": {
+		"invalid_direction": {
 			blockStateBuilder: func(ctrl *gomock.Controller) BlockState {
 				return nil
 			},
diff --git a/dot/sync/mocks_test.go b/dot/sync/mocks_test.go
index ef16cd6ea2..45f1efd5d0 100644
--- a/dot/sync/mocks_test.go
+++ b/dot/sync/mocks_test.go
@@ -322,6 +322,21 @@ func (mr *MockBlockStateMockRecorder) IsDescendantOf(arg0, arg1 interface{}) *go
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "IsDescendantOf", reflect.TypeOf((*MockBlockState)(nil).IsDescendantOf), arg0, arg1)
 }
 
+// Range mocks base method.
+func (m *MockBlockState) Range(arg0, arg1 common.Hash) ([]common.Hash, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Range", arg0, arg1)
+	ret0, _ := ret[0].([]common.Hash)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// Range indicates an expected call of Range.
+func (mr *MockBlockStateMockRecorder) Range(arg0, arg1 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Range", reflect.TypeOf((*MockBlockState)(nil).Range), arg0, arg1)
+}
+
 // RangeInMemory mocks base method.
 func (m *MockBlockState) RangeInMemory(arg0, arg1 common.Hash) ([]common.Hash, error) {
 	m.ctrl.T.Helper()