Add tests

dns/resolver.go

@@ -47,8 +47,13 @@ func (f FuncResolver) Query(ctx context.Context, q dnsmessage.Question) (*dnsmes
 }
 
 // NewQuestion is a convenience function to create a [dnsmessage.Question].
+// The input domain is interpreted as fully-qualified. If the end "." is missing, it's added.
 func NewQuestion(domain string, qtype dnsmessage.Type) (*dnsmessage.Question, error) {
-	name, err := dnsmessage.NewName(domain)
+	fullDomain := domain
+	if len(domain) == 0 || domain[len(domain)-1] != '.' {
+		fullDomain += "."
+	}
+	name, err := dnsmessage.NewName(fullDomain)
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse domain name: %w", err)
 	}

dns/resolver_test.go

@@ -0,0 +1,97 @@
+// Copyright 2023 Jigsaw Operations LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package dns
+
+import (
+	"encoding/binary"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"golang.org/x/net/dns/dnsmessage"
+)
+
+func TestNewQuestionTypes(t *testing.T) {
+	testDomain := "example.com."
+	qname, err := dnsmessage.NewName(testDomain)
+	require.NoError(t, err)
+	for _, qtype := range []dnsmessage.Type{dnsmessage.TypeA, dnsmessage.TypeAAAA, dnsmessage.TypeCNAME} {
+		t.Run(qtype.String(), func(t *testing.T) {
+			q, err := NewQuestion(testDomain, qtype)
+			require.NoError(t, err)
+			require.Equal(t, qname, q.Name)
+			require.Equal(t, qtype, q.Type)
+			require.Equal(t, dnsmessage.ClassINET, q.Class)
+		})
+	}
+}
+
+func TestNewQuestionNotFQDN(t *testing.T) {
+	testDomain := "example.com"
+	q, err := NewQuestion(testDomain, dnsmessage.TypeAAAA)
+	require.NoError(t, err)
+	require.Equal(t, dnsmessage.MustNewName("example.com."), q.Name)
+}
+
+func TestNewQuestionRoot(t *testing.T) {
+	testDomain := "."
+	qname, err := dnsmessage.NewName(testDomain)
+	require.NoError(t, err)
+	q, err := NewQuestion(testDomain, dnsmessage.TypeAAAA)
+	require.NoError(t, err)
+	require.Equal(t, qname, q.Name)
+}
+
+func TestNewQuestionEmpty(t *testing.T) {
+	testDomain := ""
+	q, err := NewQuestion(testDomain, dnsmessage.TypeAAAA)
+	require.NoError(t, err)
+	require.Equal(t, dnsmessage.MustNewName("."), q.Name)
+}
+
+func Test_appendRequest(t *testing.T) {
+	q, err := NewQuestion(".", dnsmessage.TypeAAAA)
+	require.NoError(t, err)
+
+	id := uint16(1234)
+	buf, err := appendRequest(id, *q, []byte{})
+	require.NoError(t, err)
+
+	// 12 bytes header + 5 question + 11 EDNS(0) OPT RR
+	require.Equal(t, 28, len(buf))
+
+	require.Equal(t, id, binary.BigEndian.Uint16(buf))
+
+	var request dnsmessage.Message
+	err = request.Unpack(buf)
+	require.NoError(t, err)
+	require.Equal(t, id, request.ID)
+	require.Equal(t, 1, len(request.Questions))
+	require.Equal(t, *q, request.Questions[0])
+	require.Equal(t, 0, len(request.Answers))
+	require.Equal(t, 0, len(request.Authorities))
+	// ENDS(0) OPT resource record.
+	require.Equal(t, 1, len(request.Additionals))
+	optRR := dnsmessage.Resource{
+		Header: dnsmessage.ResourceHeader{
+			Name:   dnsmessage.MustNewName("."),
+			Type:   dnsmessage.TypeOPT,
+			Class:  maxDNSPacketSize,
+			TTL:    0,
+			Length: 0,
+		},
+		Body: &dnsmessage.OPTResource{},
+	}
+	require.Equal(t, optRR, request.Additionals[0])
+}