Function TestSummaryDecay

prometheus/summary_test.go:373–408

(t *testing.T)

}

func TestSummaryDecay(t *testing.T) {
	now := time.Now()

	sum := NewSummary(SummaryOpts{
		Name:       "test_summary",
		Help:       "helpless",
		MaxAge:     100 * time.Millisecond,
		Objectives: map[float64]float64{0.1: 0.001},
		AgeBuckets: 10,
		now: func() time.Time {
			return now
		},
	})

	m := &dto.Metric{}
	for i := 1; i <= 1000; i++ {
		now = now.Add(time.Millisecond)
		sum.Observe(float64(i))
		if i%10 == 0 {
			sum.Write(m)
			got := *m.Summary.Quantile[0].Value
			want := math.Max(float64(i)/10, float64(i-90))
			if math.Abs(got-want) > 20 {
				t.Errorf("%d. got %f, want %f", i, got, want)
			}
			m.Reset()
		}
	}

	// Simulate waiting for MaxAge without observations
	now = now.Add(100 * time.Millisecond)
	sum.Write(m)
	if got := *m.Summary.Quantile[0].Value; !math.IsNaN(got) {
		t.Errorf("got %f, want NaN after expiration", got)
	}
}

func getBounds(vars []float64, q, ε float64) (minBound, maxBound float64) {
	// TODO(beorn7): This currently tolerates an error of up to 2*ε. The