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// Copyright 2009 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 net
import (
"flag"
"fmt"
"testing"
"time"
)
var testDNSFlood = flag.Bool("dnsflood", false, "whether to test dns query flooding")
func TestDNSThreadLimit(t *testing.T) {
if !*testDNSFlood {
t.Skip("test disabled; use -dnsflood to enable")
}
const N = 10000
c := make(chan int, N)
for i := 0; i < N; i++ {
go func(i int) {
LookupIP(fmt.Sprintf("%d.net-test.golang.org", i))
c <- 1
}(i)
}
// Don't bother waiting for the stragglers; stop at 0.9 N.
for i := 0; i < N*9/10; i++ {
if i%100 == 0 {
//println("TestDNSThreadLimit:", i)
}
<-c
}
// If we're still here, it worked.
}
func TestLookupIPDeadline(t *testing.T) {
if !*testDNSFlood {
t.Skip("test disabled; use -dnsflood to enable")
}
const N = 5000
const timeout = 3 * time.Second
c := make(chan error, 2*N)
for i := 0; i < N; i++ {
name := fmt.Sprintf("%d.net-test.golang.org", i)
go func() {
_, err := lookupIPDeadline(name, time.Now().Add(timeout/2))
c <- err
}()
go func() {
_, err := lookupIPDeadline(name, time.Now().Add(timeout))
c <- err
}()
}
qstats := struct {
succeeded, failed int
timeout, temporary, other int
unknown int
}{}
deadline := time.After(timeout + time.Second)
for i := 0; i < 2*N; i++ {
select {
case <-deadline:
t.Fatal("deadline exceeded")
case err := <-c:
switch err := err.(type) {
case nil:
qstats.succeeded++
case Error:
qstats.failed++
if err.Timeout() {
qstats.timeout++
}
if err.Temporary() {
qstats.temporary++
}
if !err.Timeout() && !err.Temporary() {
qstats.other++
}
default:
qstats.failed++
qstats.unknown++
}
}
}
// A high volume of DNS queries for sub-domain of golang.org
// would be coordinated by authoritative or recursive server,
// or stub resolver which implements query-response rate
// limitation, so we can expect some query successes and more
// failures including timeout, temporary and other here.
// As a rule, unknown must not be shown but it might possibly
// happen due to issue 4856 for now.
t.Logf("%v succeeded, %v failed (%v timeout, %v temporary, %v other, %v unknown)", qstats.succeeded, qstats.failed, qstats.timeout, qstats.temporary, qstats.other, qstats.unknown)
}
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