Switch plugin API to use an accumulator

testutil/accumulator.go

@@ -0,0 +1,25 @@
+package testutil
+
+type Point struct {
+	Name  string
+	Value interface{}
+	Tags  map[string]string
+}
+
+type Accumulator struct {
+	Points []*Point
+}
+
+func (a *Accumulator) Add(name string, value interface{}, tags map[string]string) {
+	a.Points = append(a.Points, &Point{name, value, tags})
+}
+
+func (a *Accumulator) CheckValue(name string, val interface{}) bool {
+	for _, p := range a.Points {
+		if p.Name == name {
+			return p.Value == val
+		}
+	}
+
+	return false
+}