// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package trace
import (
"math"
"testing"
)
type sumTest struct {
value int64
sum int64
sumOfSquares float64
total int64
}
var sumTests = []sumTest{
{100, 100, 10000, 1},
{50, 150, 12500, 2},
{50, 200, 15000, 3},
{50, 250, 17500, 4},
}
type bucketingTest struct {
in int64
log int
bucket int
}
var bucketingTests = []bucketingTest{
{0, 0, 0},
{1, 1, 0},
{2, 2, 1},
{3, 2, 1},
{4, 3, 2},
{1000, 10, 9},
{1023, 10, 9},
{1024, 11, 10},
{1000000, 20, 19},
}
type multiplyTest struct {
in int64
ratio float64
expectedSum int64
expectedTotal int64
expectedSumOfSquares float64
}
var multiplyTests = []multiplyTest{
{15, 2.5, 37, 2, 562.5},
{128, 4.6, 758, 13, 77953.9},
}
type percentileTest struct {
fraction float64
expected int64
}
var percentileTests = []percentileTest{
{0.25, 48},
{0.5, 96},
{0.6, 109},
{0.75, 128},
{0.90, 205},
{0.95, 230},
{0.99, 256},
}
func TestSum(t *testing.T) {
var h histogram
for _, test := range sumTests {
h.addMeasurement(test.value)
sum := h.sum
if sum != test.sum {
t.Errorf("h.Sum = %v WANT: %v", sum, test.sum)
}
sumOfSquares := h.sumOfSquares
if sumOfSquares != test.sumOfSquares {
t.Errorf("h.SumOfSquares = %v WANT: %v", sumOfSquares, test.sumOfSquares)
}
total := h.total()
if total != test.total {
t.Errorf("h.Total = %v WANT: %v", total, test.total)
}
}
}
func TestMultiply(t *testing.T) {
var h histogram
for i, test := range multiplyTests {
h.addMeasurement(test.in)
h.Multiply(test.ratio)
if h.sum != test.expectedSum {
t.Errorf("#%v: h.sum = %v WANT: %v", i, h.sum, test.expectedSum)
}
if h.total() != test.expectedTotal {
t.Errorf("#%v: h.total = %v WANT: %v", i, h.total(), test.expectedTotal)
}
if h.sumOfSquares != test.expectedSumOfSquares {
t.Errorf("#%v: h.SumOfSquares = %v WANT: %v", i, test.expectedSumOfSquares, h.sumOfSquares)
}
}
}
func TestBucketingFunctions(t *testing.T) {
for _, test := range bucketingTests {
log := log2(test.in)
if log != test.log {
t.Errorf("log2 = %v WANT: %v", log, test.log)
}
bucket := getBucket(test.in)
if bucket != test.bucket {
t.Errorf("getBucket = %v WANT: %v", bucket, test.bucket)
}
}
}
func TestAverage(t *testing.T) {
a := new(histogram)
average := a.average()
if average != 0 {
t.Errorf("Average of empty histogram was %v WANT: 0", average)
}
a.addMeasurement(1)
a.addMeasurement(1)
a.addMeasurement(3)
const expected = float64(5) / float64(3)
average = a.average()
if !isApproximate(average, expected) {
t.Errorf("Average = %g WANT: %v", average, expected)
}
}
func TestStandardDeviation(t *testing.T) {
a := new(histogram)
add(a, 10, 1<<4)
add(a, 10, 1<<5)
add(a, 10, 1<<6)
stdDev := a.standardDeviation()
const expected = 19.95
if !isApproximate(stdDev, expected) {
t.Errorf("StandardDeviation = %v WANT: %v", stdDev, expected)
}
// No values
a = new(histogram)
stdDev = a.standardDeviation()
if !isApproximate(stdDev, 0) {
t.Errorf("StandardDeviation = %v WANT: 0", stdDev)
}
add(a, 1, 1<<4)
if !isApproximate(stdDev, 0) {
t.Errorf("StandardDeviation = %v WANT: 0", stdDev)
}
add(a, 10, 1<<4)
if !isApproximate(stdDev, 0) {
t.Errorf("StandardDeviation = %v WANT: 0", stdDev)
}
}
func TestPercentileBoundary(t *testing.T) {
a := new(histogram)
add(a, 5, 1<<4)
add(a, 10, 1<<6)
add(a, 5, 1<<7)
for _, test := range percentileTests {
percentile := a.percentileBoundary(test.fraction)
if percentile != test.expected {
t.Errorf("h.PercentileBoundary (fraction=%v) = %v WANT: %v", test.fraction, percentile, test.expected)
}
}
}
func TestCopyFrom(t *testing.T) {
a := histogram{5, 25, []int64{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38}, 4, -1}
b := histogram{6, 36, []int64{2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39}, 5, -1}
a.CopyFrom(&b)
if a.String() != b.String() {
t.Errorf("a.String = %s WANT: %s", a.String(), b.String())
}
}
func TestClear(t *testing.T) {
a := histogram{5, 25, []int64{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38}, 4, -1}
a.Clear()
expected := "0, 0.000000, 0, 0, []"
if a.String() != expected {
t.Errorf("a.String = %s WANT %s", a.String(), expected)
}
}
func TestNew(t *testing.T) {
a := histogram{5, 25, []int64{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38}, 4, -1}
b := a.New()
expected := "0, 0.000000, 0, 0, []"
if b.(*histogram).String() != expected {
t.Errorf("b.(*histogram).String = %s WANT: %s", b.(*histogram).String(), expected)
}
}
func TestAdd(t *testing.T) {
// The tests here depend on the associativity of addMeasurement and Add.
// Add empty observation
a := histogram{5, 25, []int64{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38}, 4, -1}
b := a.New()
expected := a.String()
a.Add(b)
if a.String() != expected {
t.Errorf("a.String = %s WANT: %s", a.String(), expected)
}
// Add same bucketed value, no new buckets
c := new(histogram)
d := new(histogram)
e := new(histogram)
c.addMeasurement(12)
d.addMeasurement(11)
e.addMeasurement(12)
e.addMeasurement(11)
c.Add(d)
if c.String() != e.String() {
t.Errorf("c.String = %s WANT: %s", c.String(), e.String())
}
// Add bucketed values
f := new(histogram)
g := new(histogram)
h := new(histogram)
f.addMeasurement(4)
f.addMeasurement(12)
f.addMeasurement(100)
g.addMeasurement(18)
g.addMeasurement(36)
g.addMeasurement(255)
h.addMeasurement(4)
h.addMeasurement(12)
h.addMeasurement(100)
h.addMeasurement(18)
h.addMeasurement(36)
h.addMeasurement(255)
f.Add(g)
if f.String() != h.String() {
t.Errorf("f.String = %q WANT: %q", f.String(), h.String())
}
// add buckets to no buckets
i := new(histogram)
j := new(histogram)
k := new(histogram)
j.addMeasurement(18)
j.addMeasurement(36)
j.addMeasurement(255)
k.addMeasurement(18)
k.addMeasurement(36)
k.addMeasurement(255)
i.Add(j)
if i.String() != k.String() {
t.Errorf("i.String = %q WANT: %q", i.String(), k.String())
}
// add buckets to single value (no overlap)
l := new(histogram)
m := new(histogram)
n := new(histogram)
l.addMeasurement(0)
m.addMeasurement(18)
m.addMeasurement(36)
m.addMeasurement(255)
n.addMeasurement(0)
n.addMeasurement(18)
n.addMeasurement(36)
n.addMeasurement(255)
l.Add(m)
if l.String() != n.String() {
t.Errorf("l.String = %q WANT: %q", l.String(), n.String())
}
// mixed order
o := new(histogram)
p := new(histogram)
o.addMeasurement(0)
o.addMeasurement(2)
o.addMeasurement(0)
p.addMeasurement(0)
p.addMeasurement(0)
p.addMeasurement(2)
if o.String() != p.String() {
t.Errorf("o.String = %q WANT: %q", o.String(), p.String())
}
}
func add(h *histogram, times int, val int64) {
for i := 0; i < times; i++ {
h.addMeasurement(val)
}
}
func isApproximate(x, y float64) bool {
return math.Abs(x-y) < 1e-2
}