134 lines
3.3 KiB
Go
134 lines
3.3 KiB
Go
package metrics
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import (
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"fmt"
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"math"
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"reflect"
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"runtime/metrics"
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"testing"
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)
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var _ Histogram = (*runtimeHistogram)(nil)
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type runtimeHistogramTest struct {
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h metrics.Float64Histogram
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Count int64
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Min int64
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Max int64
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Sum int64
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Mean float64
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Variance float64
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StdDev float64
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Percentiles []float64 // .5 .8 .9 .99 .995
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}
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// This test checks the results of statistical functions implemented
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// by runtimeHistogramSnapshot.
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func TestRuntimeHistogramStats(t *testing.T) {
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tests := []runtimeHistogramTest{
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0: {
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h: metrics.Float64Histogram{
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Counts: []uint64{},
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Buckets: []float64{},
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},
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Count: 0,
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Max: 0,
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Min: 0,
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Sum: 0,
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Mean: 0,
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Variance: 0,
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StdDev: 0,
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Percentiles: []float64{0, 0, 0, 0, 0},
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},
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1: {
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// This checks the case where the highest bucket is +Inf.
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h: metrics.Float64Histogram{
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Counts: []uint64{0, 1, 2},
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Buckets: []float64{0, 0.5, 1, math.Inf(1)},
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},
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Count: 3,
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Max: 1,
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Min: 0,
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Sum: 3,
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Mean: 0.9166666,
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Percentiles: []float64{1, 1, 1, 1, 1},
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Variance: 0.020833,
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StdDev: 0.144433,
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},
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2: {
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h: metrics.Float64Histogram{
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Counts: []uint64{8, 6, 3, 1},
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Buckets: []float64{12, 16, 18, 24, 25},
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},
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Count: 18,
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Max: 25,
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Min: 12,
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Sum: 270,
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Mean: 16.75,
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Variance: 10.3015,
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StdDev: 3.2096,
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Percentiles: []float64{16, 18, 18, 24, 24},
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},
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}
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for i, test := range tests {
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t.Run(fmt.Sprint(i), func(t *testing.T) {
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s := runtimeHistogramSnapshot(test.h)
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if v := s.Count(); v != test.Count {
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t.Errorf("Count() = %v, want %v", v, test.Count)
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}
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if v := s.Min(); v != test.Min {
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t.Errorf("Min() = %v, want %v", v, test.Min)
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}
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if v := s.Max(); v != test.Max {
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t.Errorf("Max() = %v, want %v", v, test.Max)
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}
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if v := s.Sum(); v != test.Sum {
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t.Errorf("Sum() = %v, want %v", v, test.Sum)
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}
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if v := s.Mean(); !approxEqual(v, test.Mean, 0.0001) {
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t.Errorf("Mean() = %v, want %v", v, test.Mean)
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}
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if v := s.Variance(); !approxEqual(v, test.Variance, 0.0001) {
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t.Errorf("Variance() = %v, want %v", v, test.Variance)
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}
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if v := s.StdDev(); !approxEqual(v, test.StdDev, 0.0001) {
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t.Errorf("StdDev() = %v, want %v", v, test.StdDev)
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}
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ps := []float64{.5, .8, .9, .99, .995}
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if v := s.Percentiles(ps); !reflect.DeepEqual(v, test.Percentiles) {
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t.Errorf("Percentiles(%v) = %v, want %v", ps, v, test.Percentiles)
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}
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})
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}
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}
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func approxEqual(x, y, ε float64) bool {
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if math.IsInf(x, -1) && math.IsInf(y, -1) {
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return true
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}
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if math.IsInf(x, 1) && math.IsInf(y, 1) {
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return true
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}
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if math.IsNaN(x) && math.IsNaN(y) {
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return true
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}
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return math.Abs(x-y) < ε
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}
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// This test verifies that requesting Percentiles in unsorted order
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// returns them in the requested order.
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func TestRuntimeHistogramStatsPercentileOrder(t *testing.T) {
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p := runtimeHistogramSnapshot{
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Counts: []uint64{1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
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Buckets: []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10},
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}
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result := p.Percentiles([]float64{1, 0.2, 0.5, 0.1, 0.2})
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expected := []float64{10, 2, 5, 1, 2}
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if !reflect.DeepEqual(result, expected) {
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t.Fatal("wrong result:", result)
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}
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}
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