Added AddTo() and FromFormat()

msg.go

@@ -133,11 +133,27 @@ func (m *Msg) From(f string) error {
 	return m.SetAddrHeader(HeaderFrom, f)
 }
 
+// FromFormat takes a name and address, formats them RFC5322 compliant and stores them as
+// the From address header field
+func (m *Msg) FromFormat(n, a string) error {
+	return m.SetAddrHeader(HeaderFrom, fmt.Sprintf(`"%s" <%s>`, n, a))
+}
+
 // To takes and validates a given mail address list sets the To: addresses of the Msg
 func (m *Msg) To(t ...string) error {
 	return m.SetAddrHeader(HeaderTo, t...)
 }
 
+// AddTo adds an additional address to the To address header field
+func (m *Msg) AddTo(t string) error {
+	var tl []string
+	for _, ct := range m.addrHeader[HeaderTo] {
+		tl = append(tl, ct.String())
+	}
+	tl = append(tl, t)
+	return m.To(tl...)
+}
+
 // Subject sets the "Subject" header field of the Msg
 func (m *Msg) Subject(s string) {
 	m.SetHeader(HeaderSubject, s)

msg_test.go

@@ -0,0 +1,78 @@
+package mail
+
+import (
+	"net/mail"
+	"testing"
+)
+
+// TestMsg_AddTo tests the AddTo() method for the Msg object
+func TestMsg_AddTo(t *testing.T) {
+	a := []string{"address1@example.com", "address2@example.com"}
+	na := "address3@example.com"
+	m := NewMsg()
+	if err := m.To(a...); err != nil {
+		t.Errorf("failed to set TO addresses: %s", err)
+		return
+	}
+	if err := m.AddTo(na); err != nil {
+		t.Errorf("AddTo failed: %s", err)
+		return
+	}
+
+	atf := false
+	for _, v := range m.addrHeader[HeaderTo] {
+		if v.Address == na {
+			atf = true
+		}
+	}
+	if !atf {
+		t.Errorf("AddTo() failed. Address %q not found in TO address slice.", na)
+	}
+}
+
+// TestMsg_FromFormat tests the FromFormat() method for the Msg object
+func TestMsg_FromFormat(t *testing.T) {
+	tests := []struct {
+		tname string
+		name  string
+		addr  string
+		want  string
+		fail  bool
+	}{
+		{"valid name and addr", "Toni Tester", "tester@example.com",
+			`"Toni Tester" <tester@example.com>`, false},
+		{"no name with valid addr", "", "tester@example.com",
+			`<tester@example.com>`, false},
+		{"valid name with invalid addr", "Toni Tester", "@example.com",
+			``, true},
+	}
+
+	m := NewMsg()
+	for _, tt := range tests {
+		t.Run(tt.tname, func(t *testing.T) {
+			if err := m.FromFormat(tt.name, tt.addr); err != nil && !tt.fail {
+				t.Errorf("failed to FromFormat(): %s", err)
+				return
+			}
+
+			var fa *mail.Address
+			f, ok := m.addrHeader[HeaderFrom]
+			if ok && len(f) > 0 {
+				fa = f[0]
+			}
+			if (!ok || len(f) == 0) && !tt.fail {
+				t.Errorf(`valid from address expected, but "From:" field is empty`)
+				return
+			}
+			if tt.fail && len(f) > 0 {
+				t.Errorf("FromFormat() was supposed to failed but got value: %s", fa.String())
+				return
+			}
+
+			if !tt.fail && fa.String() != tt.want {
+				t.Errorf("wrong result for FromFormat(). Want: %s, got: %s", tt.want, fa.String())
+			}
+			m.addrHeader[HeaderFrom] = nil
+		})
+	}
+}