Remove outputs blocking inputs when output is slow (#4938)

testutil/accumulator.go

@@ -14,6 +14,15 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+var (
+	lastID uint64
+)
+
+func newTrackingID() telegraf.TrackingID {
+	atomic.AddUint64(&lastID, 1)
+	return telegraf.TrackingID(lastID)
+}
+
 // Metric defines a single point measurement
 type Metric struct {
 	Measurement string
@@ -23,7 +32,7 @@ type Metric struct {
 }
 
 func (p *Metric) String() string {
-	return fmt.Sprintf("%s %v", p.Measurement, p.Fields)
+	return fmt.Sprintf("%s %v %v", p.Measurement, p.Tags, p.Fields)
 }
 
 // Accumulator defines a mocked out accumulator
@@ -31,11 +40,12 @@ type Accumulator struct {
 	sync.Mutex
 	*sync.Cond
 
-	Metrics  []*Metric
-	nMetrics uint64
-	Discard  bool
-	Errors   []error
-	debug    bool
+	Metrics   []*Metric
+	nMetrics  uint64
+	Discard   bool
+	Errors    []error
+	debug     bool
+	delivered chan telegraf.DeliveryInfo
 }
 
 func (a *Accumulator) NMetrics() uint64 {
@@ -154,6 +164,33 @@ func (a *Accumulator) AddHistogram(
 	a.AddFields(measurement, fields, tags, timestamp...)
 }
 
+func (a *Accumulator) AddMetric(m telegraf.Metric) {
+	a.AddFields(m.Name(), m.Fields(), m.Tags(), m.Time())
+}
+
+func (a *Accumulator) WithTracking(maxTracked int) telegraf.TrackingAccumulator {
+	return a
+}
+
+func (a *Accumulator) AddTrackingMetric(m telegraf.Metric) telegraf.TrackingID {
+	a.AddMetric(m)
+	return newTrackingID()
+}
+
+func (a *Accumulator) AddTrackingMetricGroup(group []telegraf.Metric) telegraf.TrackingID {
+	for _, m := range group {
+		a.AddMetric(m)
+	}
+	return newTrackingID()
+}
+
+func (a *Accumulator) Delivered() <-chan telegraf.DeliveryInfo {
+	if a.delivered == nil {
+		a.delivered = make(chan telegraf.DeliveryInfo)
+	}
+	return a.delivered
+}
+
 // AddError appends the given error to Accumulator.Errors.
 func (a *Accumulator) AddError(err error) {
 	if err == nil {

testutil/metric.go

@@ -41,6 +41,18 @@ func newMetricDiff(metric telegraf.Metric) *metricDiff {
 	return m
 }
 
+func MetricEqual(expected, actual telegraf.Metric) bool {
+	var lhs, rhs *metricDiff
+	if expected != nil {
+		lhs = newMetricDiff(expected)
+	}
+	if actual != nil {
+		rhs = newMetricDiff(actual)
+	}
+
+	return cmp.Equal(lhs, rhs)
+}
+
 func RequireMetricEqual(t *testing.T, expected, actual telegraf.Metric) {
 	t.Helper()
 
@@ -60,11 +72,11 @@ func RequireMetricEqual(t *testing.T, expected, actual telegraf.Metric) {
 func RequireMetricsEqual(t *testing.T, expected, actual []telegraf.Metric) {
 	t.Helper()
 
-	lhs := make([]*metricDiff, len(expected))
+	lhs := make([]*metricDiff, 0, len(expected))
 	for _, m := range expected {
 		lhs = append(lhs, newMetricDiff(m))
 	}
-	rhs := make([]*metricDiff, len(actual))
+	rhs := make([]*metricDiff, 0, len(actual))
 	for _, m := range actual {
 		rhs = append(rhs, newMetricDiff(m))
 	}