feat: render models.Points to string (#17266)

Signed-off-by: Chris Goller <goller@gmail.com>

models/points.go

@@ -236,13 +236,32 @@ type FieldIterator interface {
 type Points []Point
 
 // Len implements sort.Interface.
-func (a Points) Len() int { return len(a) }
+func (p Points) Len() int { return len(p) }
 
 // Less implements sort.Interface.
-func (a Points) Less(i, j int) bool { return a[i].Time().Before(a[j].Time()) }
+func (p Points) Less(i, j int) bool { return p[i].Time().Before(p[j].Time()) }
 
 // Swap implements sort.Interface.
-func (a Points) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
+func (p Points) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
+
+func (p Points) String() string {
+	const sep = "\n"
+	switch len(p) {
+	case 0:
+		return ""
+	case 1:
+		return p[0].String()
+	}
+	var b strings.Builder
+	b.WriteString(p[0].String())
+
+	for _, s := range p[1:] {
+		b.WriteString(sep)
+		b.WriteString(s.String())
+	}
+
+	return b.String()
+}
 
 // point is the default implementation of Point.
 type point struct {

models/points_test.go

@@ -160,7 +160,7 @@ func TestPoint_Tags(t *testing.T) {
 }
 
 func TestPoint_StringSize(t *testing.T) {
-	testPoint_cube(t, func(p models.Point) {
+	testPointCube(t, func(p models.Point) {
 		l := p.StringSize()
 		s := p.String()
 
@@ -171,7 +171,7 @@ func TestPoint_StringSize(t *testing.T) {
 }
 
 func TestPoint_AppendString(t *testing.T) {
-	testPoint_cube(t, func(p models.Point) {
+	testPointCube(t, func(p models.Point) {
 		got := p.AppendString(nil)
 		exp := []byte(p.String())
 
@@ -181,7 +181,7 @@ func TestPoint_AppendString(t *testing.T) {
 	})
 }
 
-func testPoint_cube(t *testing.T, f func(p models.Point)) {
+func testPointCube(t *testing.T, f func(p models.Point)) {
 	// heard of a table-driven test? let's make a cube-driven test...
 	tagList := []models.Tags{nil, {models.NewTag([]byte("foo"), []byte("bar"))}, tags}
 	fieldList := []models.Fields{{"a": 42.0}, {"a": 42, "b": "things"}, fields}
@@ -1278,6 +1278,37 @@ func TestParsePointUnescape(t *testing.T) {
 			time.Unix(0, 0)))
 }
 
+func TestPoints_String(t *testing.T) {
+	tags := models.NewTags(map[string]string{
+		"t1": "v1",
+		"t2": "v2",
+	})
+	pts := make(models.Points, 5)
+	for i := 0; i < len(pts); i++ {
+		point, err := models.NewPoint(
+			"m1",
+			tags,
+			models.Fields{
+				"f1": i,
+			},
+			time.Unix(0, int64(i)),
+		)
+		if err != nil {
+			t.Fatalf("unable to create point %v", err)
+		}
+		pts[i] = point
+	}
+	got := pts.String()
+	want := `m1,t1=v1,t2=v2 f1=0i 0
+m1,t1=v1,t2=v2 f1=1i 1
+m1,t1=v1,t2=v2 f1=2i 2
+m1,t1=v1,t2=v2 f1=3i 3
+m1,t1=v1,t2=v2 f1=4i 4`
+	if got != want {
+		t.Errorf("Points.String() %v| \n want \n%v", got, want)
+	}
+}
+
 func TestParsePointWithTags(t *testing.T) {
 	testParsePoints(t,
 		"cpu,host=serverA,region=us-east value=1.0 1000000000", "mm",