dnsclient_test.go

Documentation: net

		 1  // Copyright 2014 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 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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