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Source file
src/net/dnsclient_test.go
Documentation: net
1
2
3
4
5 package net
6
7 import (
8 "testing"
9 )
10
11 func checkDistribution(t *testing.T, data []*SRV, margin float64) {
12 sum := 0
13 for _, srv := range data {
14 sum += int(srv.Weight)
15 }
16
17 results := make(map[string]int)
18
19 count := 10000
20 for j := 0; j < count; j++ {
21 d := make([]*SRV, len(data))
22 copy(d, data)
23 byPriorityWeight(d).shuffleByWeight()
24 key := d[0].Target
25 results[key] = results[key] + 1
26 }
27
28 actual := results[data[0].Target]
29 expected := float64(count) * float64(data[0].Weight) / float64(sum)
30 diff := float64(actual) - expected
31 t.Logf("actual: %v diff: %v e: %v m: %v", actual, diff, expected, margin)
32 if diff < 0 {
33 diff = -diff
34 }
35 if diff > (expected * margin) {
36 t.Errorf("missed target weight: expected %v, %v", expected, actual)
37 }
38 }
39
40 func testUniformity(t *testing.T, size int, margin float64) {
41 data := make([]*SRV, size)
42 for i := 0; i < size; i++ {
43 data[i] = &SRV{Target: string('a' + rune(i)), Weight: 1}
44 }
45 checkDistribution(t, data, margin)
46 }
47
48 func TestDNSSRVUniformity(t *testing.T) {
49 testUniformity(t, 2, 0.05)
50 testUniformity(t, 3, 0.10)
51 testUniformity(t, 10, 0.20)
52 testWeighting(t, 0.05)
53 }
54
55 func testWeighting(t *testing.T, margin float64) {
56 data := []*SRV{
57 {Target: "a", Weight: 60},
58 {Target: "b", Weight: 30},
59 {Target: "c", Weight: 10},
60 }
61 checkDistribution(t, data, margin)
62 }
63
64 func TestWeighting(t *testing.T) {
65 testWeighting(t, 0.05)
66 }
67
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