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// 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 net
import (
"context"
"runtime"
"testing"
)
func allResolvers(t *testing.T, f func(t *testing.T)) {
t.Run("default resolver", f)
t.Run("forced go resolver", func(t *testing.T) {
// On plan9 the forceGoDNS might not force the go resolver, currently
// it is only forced when the Resolver.Dial field is populated.
// See conf.go mustUseGoResolver.
defer forceGoDNS()()
f(t)
})
t.Run("forced cgo resolver", func(t *testing.T) {
defer forceCgoDNS()()
f(t)
})
}
// forceGoDNS forces the resolver configuration to use the pure Go resolver
// and returns a fixup function to restore the old settings.
func forceGoDNS() func() {
c := systemConf()
oldGo := c.netGo
oldCgo := c.netCgo
fixup := func() {
c.netGo = oldGo
c.netCgo = oldCgo
}
c.netGo = true
c.netCgo = false
return fixup
}
// forceCgoDNS forces the resolver configuration to use the cgo resolver
// and returns a fixup function to restore the old settings.
func forceCgoDNS() func() {
c := systemConf()
oldGo := c.netGo
oldCgo := c.netCgo
fixup := func() {
c.netGo = oldGo
c.netCgo = oldCgo
}
c.netGo = false
c.netCgo = true
return fixup
}
func TestForceCgoDNS(t *testing.T) {
if !cgoAvailable {
t.Skip("cgo resolver not available")
}
defer forceCgoDNS()()
order, _ := systemConf().hostLookupOrder(nil, "go.dev")
if order != hostLookupCgo {
t.Fatalf("hostLookupOrder returned: %v, want cgo", order)
}
order, _ = systemConf().addrLookupOrder(nil, "192.0.2.1")
if order != hostLookupCgo {
t.Fatalf("addrLookupOrder returned: %v, want cgo", order)
}
if systemConf().mustUseGoResolver(nil) {
t.Fatal("mustUseGoResolver = true, want false")
}
}
func TestForceGoDNS(t *testing.T) {
var resolver *Resolver
if runtime.GOOS == "plan9" {
resolver = &Resolver{
Dial: func(_ context.Context, _, _ string) (Conn, error) {
panic("unreachable")
},
}
}
defer forceGoDNS()()
order, _ := systemConf().hostLookupOrder(resolver, "go.dev")
if order == hostLookupCgo {
t.Fatalf("hostLookupOrder returned: %v, want go resolver order", order)
}
order, _ = systemConf().addrLookupOrder(resolver, "192.0.2.1")
if order == hostLookupCgo {
t.Fatalf("addrLookupOrder returned: %v, want go resolver order", order)
}
if !systemConf().mustUseGoResolver(resolver) {
t.Fatal("mustUseGoResolver = false, want true")
}
}
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