Merge pull request #42 from yalp/FixTxtLen

Fix length computation for TXT and a testcase.

pack_test.go

@@ -0,0 +1,47 @@
+package dns
+
+import (
+	"testing"
+)
+
+func TestTxtPack(t *testing.T) {
+	// Test single entry TXT record
+	rr, err := NewRR(`_raop._tcp.local. 60 IN TXT "single value"`)
+	if err != nil {
+		t.Error("Failed to parse single value TXT record", err)
+	} else if rr, ok := rr.(*TXT); !ok {
+		t.Error("Wrong type, record should be of type TXT")
+	} else {
+		if len(rr.Txt) != 1 {
+			t.Error("Bad size of TXT value:", len(rr.Txt))
+		} else if rr.Txt[0] != "single value" {
+			t.Error("Bad single value")
+		}
+		if rr.String() != `_raop._tcp.local.	60	IN	TXT	"single value"` {
+			t.Error("Bad representation of TXT record:", rr.String())
+		}
+		if rr.len() == 10 {
+			t.Error("Bad size of serialized record:", rr.len())
+		}
+	}
+
+	// Test multi entries TXT record
+	rr, err = NewRR(`_raop._tcp.local. 60 IN TXT "a=1" "b=2" "c=3" "d=4"`)
+	if err != nil {
+		t.Error("Failed to parse multi-values TXT record", err)
+	} else if rr, ok := rr.(*TXT); !ok {
+		t.Error("Wrong type, record should be of type TXT")
+	} else {
+		if len(rr.Txt) != 4 {
+			t.Error("Bad size of TXT multi-value:", len(rr.Txt))
+		} else if rr.Txt[0] != "a=1" || rr.Txt[1] != "b=2" || rr.Txt[2] != "c=3" || rr.Txt[3] != "d=4" {
+			t.Error("Bad values in TXT records")
+		}
+		if rr.String() != `_raop._tcp.local.	60	IN	TXT	"a=1" "b=2" "c=3" "d=4"` {
+			t.Error("Bad representation of TXT multi value record:", rr.String())
+		}
+		if rr.len() != 43 {
+			t.Error("Bad size of serialized multi value record:", rr.len())
+		}
+	}
+}

types.go

@@ -487,7 +487,10 @@ func (rr *TXT) String() string {
 
 func (rr *TXT) len() int {
 	l := rr.Hdr.len()
-	for _, t := range rr.Txt {
+	for i, t := range rr.Txt {
+		if i > 0 {
+			l += 1
+		}
 		l += len(t)
 	}
 	return l