Don't serialize tokens with no values.

Fixes #3.

netrc/netrc.go

@@ -69,9 +69,15 @@ func (n *Netrc) FindMachine(name string) (m *Machine) {
 func (n *Netrc) MarshalText() (text []byte, err error) {
 	// TODO(bgentry): not safe for concurrency
 	for i := range n.tokens {
-		text = append(text, n.tokens[i].rawkind...)
 		switch n.tokens[i].kind {
-		case tkMacdef:
+		case tkComment, tkDefault, tkWhitespace: // always append these types
+			text = append(text, n.tokens[i].rawkind...)
+		default:
+			if n.tokens[i].value != "" { // skip empty-value tokens
+				text = append(text, n.tokens[i].rawkind...)
+			}
+		}
+		if n.tokens[i].kind == tkMacdef {
 			text = append(text, ' ')
 			text = append(text, n.tokens[i].macroName...)
 		}

netrc/netrc_test.go

@@ -6,14 +6,15 @@ package netrc
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"strings"
 	"testing"
 )
 
 var expectedMachines = []*Machine{
-	&Machine{Name: "mail.google.com", Login: "[email protected]", Password: "somethingSecret", Account: "gmail"},
+	&Machine{Name: "mail.google.com", Login: "[email protected]", Password: "somethingSecret", Account: "justagmail"},
 	&Machine{Name: "ray", Login: "demo", Password: "mypassword", Account: ""},
 	&Machine{Name: "weirdlogin", Login: "uname", Password: "pass#pass", Account: ""},
 	&Machine{Name: "", Login: "anonymous", Password: "[email protected]", Account: ""},
@@ -185,6 +186,18 @@ func TestMarshalText(t *testing.T) {
 	if string(result) != string(expected) {
 		t.Errorf("expected:\n%q\ngot:\n%q", string(expected), string(result))
 	}
+
+	// make sure tokens w/ no value are not serialized
+	m := n.FindMachine("mail.google.com")
+	m.UpdatePassword("")
+	result, err = n.MarshalText()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if strings.Contains(string(result), "\tpassword \n") {
+		fmt.Println(string(result))
+		t.Errorf("expected zero-value password token to not be serialzed")
+	}
 }
 
 var newMachineTests = []struct {