Merge branch 'develop'

gauge.go

@@ -1,6 +1,7 @@
 package signalfx
 
 import (
+	"math"
 	"sync/atomic"
 	"time"
 )
@@ -90,7 +91,7 @@ type StableGauge struct {
 
 // NewStableGauge returns a new StableGauge with the indicated initial state.
 func NewStableGauge(metric string, dimensions map[string]string, value int64) *StableGauge {
-	return &StableGauge{gauge: NewGauge(metric, dimensions, value)}
+	return &StableGauge{gauge: NewGauge(metric, dimensions, value), prevValue: math.MaxInt64}
 }
 
 // Record sets a gauge's internal state to the indicated value.

gauge_test.go

@@ -69,6 +69,22 @@ func TestGauge(t *testing.T) {
 		So(gdp.Value, ShouldEqual, 8)
 		So(g.prevValue, ShouldEqual, 8)
 		So(t.Before(gdp.Timestamp), ShouldBeTrue)
+
+		Convey("reports a 0 if it is the first report", func() {
+			g := NewStableGauge("stable-gauge", nil, 0)
+			So(g, ShouldNotBeNil)
+			So(g.gauge.metric, ShouldEqual, "stable-gauge")
+			So(g.gauge.dimensions, ShouldBeNil)
+			So(g.gauge.value, ShouldEqual, 0)
+
+			g.Record(0)
+			gdp := g.DataPoint()
+			So(gdp, ShouldNotBeNil)
+			So(gdp.Metric, ShouldEqual, "stable-gauge")
+			So(gdp.Dimensions, ShouldBeNil)
+			So(gdp.Value, ShouldEqual, 0)
+			So(g.prevValue, ShouldEqual, 0)
+		})
 	})
 	Convey("Broken wrapped gauges break cleanly", t, func() {
 		g := WrapGauge("broken", nil, GetterFunc(func() (interface{}, error) {