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sample_test.go
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sample_test.go
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package sample
import (
"sort"
"testing"
)
type cnt struct {
val int
count int
}
type byCount []cnt
func (c byCount) Len() int {
return len(c)
}
func (c byCount) Less(i, j int) bool {
return c[i].count < c[j].count
}
func (c byCount) Swap(i, j int) {
c[i], c[j] = c[j], c[i]
}
type byVal []cnt
func (c byVal) Len() int {
return len(c)
}
func (c byVal) Less(i, j int) bool {
return c[i].val < c[j].val
}
func (c byVal) Swap(i, j int) {
c[i], c[j] = c[j], c[i]
}
type weightedInt struct {
elt int
weight float64
}
func (w weightedInt) Weight() float64 {
return w.weight
}
func testSampleFunc(t *testing.T, sampleSize int, sf func([]Weighted, int) ([]Weighted, error)) {
counter := make(map[int]int)
var wl []Weighted
for i := 1; i < 8; i++ {
wl = append(wl, weightedInt{i, float64(i)})
}
for i := 0; i < 1024; i++ {
res, err := sf(wl, sampleSize)
if err != nil {
t.Fatal(err)
}
for _, e := range res {
v, ok := e.(weightedInt)
if !ok {
t.Fatalf("type is not weightedInt: %T", e)
}
counter[v.elt]++
}
}
var cntSlice byCount
for v, c := range counter {
cntSlice = append(cntSlice, cnt{val: v, count: c})
}
sort.Sort(cntSlice)
if !sort.IsSorted(byVal(cntSlice)) {
t.Fatalf("slice should be sorted by value: %v", cntSlice)
}
}
func TestSample(t *testing.T) {
testSampleFunc(t, 3, Sample)
}
func TestSampleChoiceFallback(t *testing.T) {
testSampleFunc(t, 1, Sample)
}
func TestChoice(t *testing.T) {
sf := func(w []Weighted, _ int) ([]Weighted, error) {
c, err := Choice(w)
return []Weighted{c}, err
}
testSampleFunc(t, 1, sf)
}
func BenchmarkSample(b *testing.B) {
var wl []Weighted
for i := 1; i < 4096; i++ {
wl = append(wl, weightedInt{i, float64(i)})
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
if _, err := Sample(wl, 1024); err != nil {
b.Fatal(err)
}
}
}