net: test dnsconfig_unix with sample resolv.conf

R=golang-dev, adg, bradfitz, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/21580043

src/pkg/net/dnsclient_unix.go

@@ -159,7 +159,8 @@ func convertRR_AAAA(records []dnsRR) []IP {
 var cfg *dnsConfig
 var dnserr error
 
-func loadConfig() { cfg, dnserr = dnsReadConfig() }
+// Assume dns config file is /etc/resolv.conf here
+func loadConfig() { cfg, dnserr = dnsReadConfig("/etc/resolv.conf") }
 
 var onceLoadConfig sync.Once
 

src/pkg/net/dnsconfig_unix.go

@@ -20,9 +20,8 @@ type dnsConfig struct {
 // See resolv.conf(5) on a Linux machine.
 // TODO(rsc): Supposed to call uname() and chop the beginning
 // of the host name to get the default search domain.
-// We assume it's in resolv.conf anyway.
-func dnsReadConfig() (*dnsConfig, error) {
-	file, err := open("/etc/resolv.conf")
+func dnsReadConfig(filename string) (*dnsConfig, error) {
+	file, err := open(filename)
 	if err != nil {
 		return nil, &DNSConfigError{err}
 	}

src/pkg/net/dnsconfig_unix_test.go

@@ -0,0 +1,48 @@
+// Copyright 2013 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.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd
+
+package net
+
+import (
+	"testing"
+)
+
+func TestReadConfig(t *testing.T) {
+	dnsConfig, err := dnsReadConfig("testdata/resolv.conf")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(dnsConfig.servers) != 1 {
+		t.Errorf("len(dnsConfig.servers) = %d; want %d", len(dnsConfig.servers), 1)
+	}
+	if dnsConfig.servers[0] != "[192.168.1.1]" {
+		t.Errorf("dnsConfig.servers[0] = %s; want %s", dnsConfig.servers[0], "[192.168.1.1]")
+	}
+
+	if len(dnsConfig.search) != 1 {
+		t.Errorf("len(dnsConfig.search) = %d; want %d", len(dnsConfig.search), 1)
+	}
+	if dnsConfig.search[0] != "Home" {
+		t.Errorf("dnsConfig.search[0] = %s; want %s", dnsConfig.search[0], "Home")
+	}
+
+	if dnsConfig.ndots != 5 {
+		t.Errorf("dnsConfig.ndots = %d; want %d", dnsConfig.ndots, 5)
+	}
+
+	if dnsConfig.timeout != 10 {
+		t.Errorf("dnsConfig.timeout = %d; want %d", dnsConfig.timeout, 10)
+	}
+
+	if dnsConfig.attempts != 3 {
+		t.Errorf("dnsConfig.attempts = %d; want %d", dnsConfig.attempts, 3)
+	}
+
+	if dnsConfig.rotate != true {
+		t.Errorf("dnsConfig.rotate = %t; want %t", dnsConfig.rotate, true)
+	}
+}

src/pkg/net/testdata/resolv.conf

@@ -0,0 +1,5 @@
+# /etc/resolv.conf
+
+domain Home
+nameserver 192.168.1.1
+options ndots:5 timeout:10 attempts:3 rotate