test: add test for series

series.go

@@ -94,6 +94,7 @@ type Series struct {
 	MarkPoint SeriesMarkPoint
 	MarkLine  SeriesMarkLine
 }
+type SeriesList []Series
 
 type PieSeriesOption struct {
 	Radius    string
@@ -158,6 +159,14 @@ func (s *Series) Summary() seriesSummary {
 	}
 }
 
+func (sl SeriesList) Names() []string {
+	names := make([]string, len(sl))
+	for index, s := range sl {
+		names[index] = s.Name
+	}
+	return names
+}
+
 type LabelFormatter func(index int, value float64, percent float64) string
 
 func NewPieLabelFormatter(seriesNames []string, layout string) LabelFormatter {