dns/dnsmessage: move example code into example_test.go

Also renames the existing example function to make it visible with
godoc command and godoc.org.

Change-Id: I0e5bef22f2a95930c59c6e79f010ba61651012cd
Reviewed-on: https://go-review.googlesource.com/46791
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
Reviewed-by: Ian Gudger <igudger@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

dns/dnsmessage/example_test.go

+// Copyright 2017 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 dnsmessage_test
+
+import (
+	"fmt"
+	"net"
+	"strings"
+
+	"golang.org/x/net/dns/dnsmessage"
+)
+
+func mustNewName(name string) dnsmessage.Name {
+	n, err := dnsmessage.NewName(name)
+	if err != nil {
+		panic(err)
+	}
+	return n
+}
+
+func ExampleParser() {
+	msg := dnsmessage.Message{
+		Header: dnsmessage.Header{Response: true, Authoritative: true},
+		Questions: []dnsmessage.Question{
+			{
+				Name:  mustNewName("foo.bar.example.com."),
+				Type:  dnsmessage.TypeA,
+				Class: dnsmessage.ClassINET,
+			},
+			{
+				Name:  mustNewName("bar.example.com."),
+				Type:  dnsmessage.TypeA,
+				Class: dnsmessage.ClassINET,
+			},
+		},
+		Answers: []dnsmessage.Resource{
+			{
+				dnsmessage.ResourceHeader{
+					Name:  mustNewName("foo.bar.example.com."),
+					Type:  dnsmessage.TypeA,
+					Class: dnsmessage.ClassINET,
+				},
+				&dnsmessage.AResource{[4]byte{127, 0, 0, 1}},
+			},
+			{
+				dnsmessage.ResourceHeader{
+					Name:  mustNewName("bar.example.com."),
+					Type:  dnsmessage.TypeA,
+					Class: dnsmessage.ClassINET,
+				},
+				&dnsmessage.AResource{[4]byte{127, 0, 0, 2}},
+			},
+		},
+	}
+
+	buf, err := msg.Pack()
+	if err != nil {
+		panic(err)
+	}
+
+	wantName := "bar.example.com."
+
+	var p dnsmessage.Parser
+	if _, err := p.Start(buf); err != nil {
+		panic(err)
+	}
+
+	for {
+		q, err := p.Question()
+		if err == dnsmessage.ErrSectionDone {
+			break
+		}
+		if err != nil {
+			panic(err)
+		}
+
+		if q.Name.String() != wantName {
+			continue
+		}
+
+		fmt.Println("Found question for name", wantName)
+		if err := p.SkipAllQuestions(); err != nil {
+			panic(err)
+		}
+		break
+	}
+
+	var gotIPs []net.IP
+	for {
+		h, err := p.AnswerHeader()
+		if err == dnsmessage.ErrSectionDone {
+			break
+		}
+		if err != nil {
+			panic(err)
+		}
+
+		if (h.Type != dnsmessage.TypeA && h.Type != dnsmessage.TypeAAAA) || h.Class != dnsmessage.ClassINET {
+			continue
+		}
+
+		if !strings.EqualFold(h.Name.String(), wantName) {
+			if err := p.SkipAnswer(); err != nil {
+				panic(err)
+			}
+			continue
+		}
+
+		switch h.Type {
+		case dnsmessage.TypeA:
+			r, err := p.AResource()
+			if err != nil {
+				panic(err)
+			}
+			gotIPs = append(gotIPs, r.A[:])
+		case dnsmessage.TypeAAAA:
+			r, err := p.AAAAResource()
+			if err != nil {
+				panic(err)
+			}
+			gotIPs = append(gotIPs, r.AAAA[:])
+		}
+	}
+
+	fmt.Printf("Found A/AAAA records for name %s: %v\n", wantName, gotIPs)
+
+	// Output:
+	// Found question for name bar.example.com.
+	// Found A/AAAA records for name bar.example.com.: [127.0.0.2]
+}

dns/dnsmessage/message_test.go

@@ -7,9 +7,7 @@ package dnsmessage
 import (
 	"bytes"
 	"fmt"
-	"net"
 	"reflect"
-	"strings"
 	"testing"
 )
 
@@ -536,117 +534,6 @@ func TestBuilder(t *testing.T) {
 	}
 }
 
-func ExampleHeaderSearch() {
-	msg := Message{
-		Header: Header{Response: true, Authoritative: true},
-		Questions: []Question{
-			{
-				Name:  mustNewName("foo.bar.example.com."),
-				Type:  TypeA,
-				Class: ClassINET,
-			},
-			{
-				Name:  mustNewName("bar.example.com."),
-				Type:  TypeA,
-				Class: ClassINET,
-			},
-		},
-		Answers: []Resource{
-			{
-				ResourceHeader{
-					Name:  mustNewName("foo.bar.example.com."),
-					Type:  TypeA,
-					Class: ClassINET,
-				},
-				&AResource{[4]byte{127, 0, 0, 1}},
-			},
-			{
-				ResourceHeader{
-					Name:  mustNewName("bar.example.com."),
-					Type:  TypeA,
-					Class: ClassINET,
-				},
-				&AResource{[4]byte{127, 0, 0, 2}},
-			},
-		},
-	}
-
-	buf, err := msg.Pack()
-	if err != nil {
-		panic(err)
-	}
-
-	wantName := "bar.example.com."
-
-	var p Parser
-	if _, err := p.Start(buf); err != nil {
-		panic(err)
-	}
-
-	for {
-		q, err := p.Question()
-		if err == ErrSectionDone {
-			break
-		}
-		if err != nil {
-			panic(err)
-		}
-
-		if q.Name.String() != wantName {
-			continue
-		}
-
-		fmt.Println("Found question for name", wantName)
-		if err := p.SkipAllQuestions(); err != nil {
-			panic(err)
-		}
-		break
-	}
-
-	var gotIPs []net.IP
-	for {
-		h, err := p.AnswerHeader()
-		if err == ErrSectionDone {
-			break
-		}
-		if err != nil {
-			panic(err)
-		}
-
-		if (h.Type != TypeA && h.Type != TypeAAAA) || h.Class != ClassINET {
-			continue
-		}
-
-		if !strings.EqualFold(h.Name.String(), wantName) {
-			if err := p.SkipAnswer(); err != nil {
-				panic(err)
-			}
-			continue
-		}
-
-		switch h.Type {
-		case TypeA:
-			r, err := p.AResource()
-			if err != nil {
-				panic(err)
-			}
-			gotIPs = append(gotIPs, r.A[:])
-		case TypeAAAA:
-			r, err := p.AAAAResource()
-			if err != nil {
-				panic(err)
-			}
-			gotIPs = append(gotIPs, r.AAAA[:])
-		}
-	}
-
-	fmt.Printf("Found A/AAAA records for name %s: %v\n", wantName, gotIPs)
-
-	// Output:
-	// Found question for name bar.example.com.
-	// Found A/AAAA records for name bar.example.com.: [127.0.0.2]
-}
-
 func BenchmarkParsing(b *testing.B) {
 	b.ReportAllocs()