client_test.go

@@ -30,6 +30,8 @@ import (
 const (
 	// DefaultHost is used as default hostname for the Client
 	DefaultHost = "127.0.0.1"
+	// TestRcpt is a trash mail address to send test mails to
+	TestRcpt = "couttifaddebro-1473@yopmail.com"
 	// TestServerProto is the protocol used for the simple SMTP test server
 	TestServerProto = "tcp"
 	// TestServerAddr is the address the simple SMTP test server listens on
@@ -3526,9 +3528,9 @@ func parseJSONLog(t *testing.T, buf *bytes.Buffer) logData {
 }
 
 // testMessage configures and returns a new email message for testing, initializing it with valid sender and recipient.
-func testMessage(t *testing.T, opts ...MsgOption) *Msg {
+func testMessage(t *testing.T) *Msg {
 	t.Helper()
-	message := NewMsg(opts...)
+	message := NewMsg()
 	if message == nil {
 		t.Fatal("failed to create new message")
 	}

msg_unix_test.go

@@ -120,27 +120,28 @@ func TestMsg_WriteToFile_unixOnly(t *testing.T) {
 	})
 }
 
-func TestMsg_WriteToTempFile_unixOnly(t *testing.T) {
+/*
-	if os.Getenv("PERFORM_UNIX_OPEN_WRITE_TESTS") != "true" {
+func TestMsg_WriteToTempFileFailed(t *testing.T) {
-		t.Skipf("PERFORM_UNIX_OPEN_WRITE_TESTS variable is not set. Skipping unix open/write tests")
+	m := NewMsg()
+	_ = m.From("Toni Tester <tester@example.com>")
+	_ = m.To("Ellenor Tester <ellinor@example.com>")
+	m.SetBodyString(TypeTextPlain, "This is a test")
+
+	curTmpDir := os.Getenv("TMPDIR")
+	defer func() {
+		if err := os.Setenv("TMPDIR", curTmpDir); err != nil {
+			t.Errorf("failed to set TMPDIR environment variable: %s", err)
+		}
+	}()
+
+	if err := os.Setenv("TMPDIR", "/invalid/directory/that/does/not/exist"); err != nil {
+		t.Errorf("failed to set TMPDIR environment variable: %s", err)
+	}
+	_, err := m.WriteToTempFile()
+	if err == nil {
+		t.Errorf("WriteToTempFile() did not fail as expected")
 	}
-
-	t.Run("WriteToTempFile fails on invalid TMPDIR", func(t *testing.T) {
-		// We store the current TMPDIR variable so we can set it back when the test is over
-		curTmpDir := os.Getenv("TMPDIR")
-		t.Cleanup(func() {
-			if err := os.Setenv("TMPDIR", curTmpDir); err != nil {
-				t.Errorf("failed to set TMPDIR environment variable: %s", err)
-			}
-		})
-
-		if err := os.Setenv("TMPDIR", "/invalid/directory/that/does/not/exist"); err != nil {
-			t.Fatalf("failed to set TMPDIR environment variable: %s", err)
-		}
-		message := testMessage(t)
-		_, err := message.WriteToTempFile()
-		if err == nil {
-			t.Errorf("expected writing to invalid TMPDIR to fail, got: %s", err)
-		}
-	})
 }
+
+
+*/

msgwriter_test.go

@@ -6,673 +6,151 @@ package mail
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
 	"io"
 	"mime"
-	"runtime"
 	"strings"
 	"testing"
 	"time"
 )
 
+// brokenWriter implements a broken writer for io.Writer testing
+type brokenWriter struct {
+	io.Writer
+}
+
+// Write implements the io.Writer interface but intentionally returns an error at
+// any time
+func (bw *brokenWriter) Write([]byte) (int, error) {
+	return 0, fmt.Errorf("intentionally failed")
+}
+
+// TestMsgWriter_Write tests the WriteTo() method of the msgWriter
 func TestMsgWriter_Write(t *testing.T) {
-	t.Run("msgWriter writes to memory for all charsets", func(t *testing.T) {
+	bw := &brokenWriter{}
-		for _, tt := range charsetTests {
+	mw := &msgWriter{writer: bw, charset: CharsetUTF8, encoder: mime.QEncoding}
-			t.Run(tt.name, func(t *testing.T) {
+	_, err := mw.Write([]byte("test"))
-				buffer := bytes.NewBuffer(nil)
+	if err == nil {
-				msgwriter := &msgWriter{
+		t.Errorf("msgWriter WriteTo() with brokenWriter should fail, but didn't")
-					writer:  buffer,
+	}
-					charset: tt.value,
+
-					encoder: mime.QEncoding,
+	// Also test the part when a previous error happened
-				}
+	mw.err = fmt.Errorf("broken")
-				_, err := msgwriter.Write([]byte("test"))
+	_, err = mw.Write([]byte("test"))
-				if err != nil {
+	if err == nil {
-					t.Errorf("msgWriter failed to write: %s", err)
+		t.Errorf("msgWriter WriteTo() with brokenWriter should fail, but didn't")
-				}
+	}
-			})
-		}
-	})
-	t.Run("msgWriter writes to memory for all encodings", func(t *testing.T) {
-		for _, tt := range encodingTests {
-			t.Run(tt.name, func(t *testing.T) {
-				buffer := bytes.NewBuffer(nil)
-				msgwriter := &msgWriter{
-					writer:  buffer,
-					charset: CharsetUTF8,
-					encoder: getEncoder(tt.value),
-				}
-				_, err := msgwriter.Write([]byte("test"))
-				if err != nil {
-					t.Errorf("msgWriter failed to write: %s", err)
-				}
-			})
-		}
-	})
-	t.Run("msgWriter should fail on write", func(t *testing.T) {
-		msgwriter := &msgWriter{
-			writer:  failReadWriteSeekCloser{},
-			charset: CharsetUTF8,
-			encoder: getEncoder(EncodingQP),
-		}
-		_, err := msgwriter.Write([]byte("test"))
-		if err == nil {
-			t.Fatalf("msgWriter was supposed to fail on write")
-		}
-	})
-	t.Run("msgWriter should fail on previous error", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter := &msgWriter{
-			writer:  buffer,
-			charset: CharsetUTF8,
-			encoder: getEncoder(EncodingQP),
-		}
-		_, err := msgwriter.Write([]byte("test"))
-		if err != nil {
-			t.Errorf("msgWriter failed to write: %s", err)
-		}
-		msgwriter.err = errors.New("intentionally failed")
-		_, err = msgwriter.Write([]byte("test2"))
-		if err == nil {
-			t.Fatalf("msgWriter was supposed to fail on second write")
-		}
-	})
 }
 
+// TestMsgWriter_writeMsg tests the writeMsg method of the msgWriter
 func TestMsgWriter_writeMsg(t *testing.T) {
-	msgwriter := &msgWriter{
+	m := NewMsg()
-		charset: CharsetUTF8,
+	_ = m.From(`"Toni Tester" <test@example.com>`)
-		encoder: getEncoder(EncodingQP),
+	_ = m.To(`"Toni Receiver" <receiver@example.com>`)
+	m.Subject("This is a subject")
+	m.SetBulk()
+	now := time.Now()
+	m.SetDateWithValue(now)
+	m.SetMessageIDWithValue("message@id.com")
+	m.SetBodyString(TypeTextPlain, "This is the body")
+	m.AddAlternativeString(TypeTextHTML, "This is the alternative body")
+	buf := bytes.Buffer{}
+	mw := &msgWriter{writer: &buf, charset: CharsetUTF8, encoder: mime.QEncoding}
+	mw.writeMsg(m)
+	ms := buf.String()
+
+	var ea []string
+	if !strings.Contains(ms, `MIME-Version: 1.0`) {
+		ea = append(ea, "MIME-Version")
 	}
-	t.Run("msgWriter writes a simple message", func(t *testing.T) {
+	if !strings.Contains(ms, fmt.Sprintf("Date: %s", now.Format(time.RFC1123Z))) {
-		buffer := bytes.NewBuffer(nil)
+		ea = append(ea, "Date")
-		now := time.Now()
-		msgwriter.writer = buffer
-		message := testMessage(t)
-		message.SetDateWithValue(now)
-		message.SetMessageIDWithValue("message@id.com")
-		message.SetBulk()
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-
-		var incorrectFields []string
-		if !strings.Contains(buffer.String(), "MIME-Version: 1.0\r\n") {
-			incorrectFields = append(incorrectFields, "MIME-Version")
-		}
-		if !strings.Contains(buffer.String(), fmt.Sprintf("Date: %s\r\n", now.Format(time.RFC1123Z))) {
-			incorrectFields = append(incorrectFields, "Date")
-		}
-		if !strings.Contains(buffer.String(), "Message-ID: <message@id.com>\r\n") {
-			incorrectFields = append(incorrectFields, "Message-ID")
-		}
-		if !strings.Contains(buffer.String(), "Precedence: bulk\r\n") {
-			incorrectFields = append(incorrectFields, "Precedence")
-		}
-		if !strings.Contains(buffer.String(), "X-Auto-Response-Suppress: All\r\n") {
-			incorrectFields = append(incorrectFields, "X-Auto-Response-Suppress")
-		}
-		if !strings.Contains(buffer.String(), "Subject: Testmail\r\n") {
-			incorrectFields = append(incorrectFields, "Subject")
-		}
-		if !strings.Contains(buffer.String(), "User-Agent: go-mail v") {
-			incorrectFields = append(incorrectFields, "User-Agent")
-		}
-		if !strings.Contains(buffer.String(), "X-Mailer: go-mail v") {
-			incorrectFields = append(incorrectFields, "X-Mailer")
-		}
-		if !strings.Contains(buffer.String(), `From: <`+TestSenderValid+`>`) {
-			incorrectFields = append(incorrectFields, "From")
-		}
-		if !strings.Contains(buffer.String(), `To: <`+TestRcptValid+`>`) {
-			incorrectFields = append(incorrectFields, "From")
-		}
-		if !strings.Contains(buffer.String(), "Content-Type: text/plain; charset=UTF-8\r\n") {
-			incorrectFields = append(incorrectFields, "Content-Type")
-		}
-		if !strings.Contains(buffer.String(), "Content-Transfer-Encoding: quoted-printable\r\n") {
-			incorrectFields = append(incorrectFields, "Content-Transfer-Encoding")
-		}
-		if !strings.HasSuffix(buffer.String(), "\r\n\r\nTestmail") {
-			incorrectFields = append(incorrectFields, "Message body")
-		}
-		if len(incorrectFields) > 0 {
-			t.Fatalf("msgWriter failed to write correct fields: %s - mail: %s",
-				strings.Join(incorrectFields, ", "), buffer.String())
-		}
-	})
-	t.Run("msgWriter with no from address uses envelope from", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := NewMsg()
-		if message == nil {
-			t.Fatal("failed to create new message")
-		}
-		if err := message.EnvelopeFrom(TestSenderValid); err != nil {
-			t.Errorf("failed to set sender address: %s", err)
-		}
-		if err := message.To(TestRcptValid); err != nil {
-			t.Errorf("failed to set recipient address: %s", err)
-		}
-		message.Subject("Testmail")
-		message.SetBodyString(TypeTextPlain, "Testmail")
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		if !strings.Contains(buffer.String(), "From: <"+TestSenderValid+">") {
-			t.Errorf("expected envelope from address as from address, got: %s", buffer.String())
-		}
-	})
-	t.Run("msgWriter with no from address or envelope from", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := NewMsg()
-		if message == nil {
-			t.Fatal("failed to create new message")
-		}
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		if strings.Contains(buffer.String(), "From:") {
-			t.Errorf("expected no from address, got: %s", buffer.String())
-		}
-	})
-	t.Run("msgWriter writes a multipart/mixed message", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t, WithBoundary("testboundary"))
-		message.AttachFile("testdata/attachment.txt")
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		if !strings.Contains(buffer.String(), "Content-Type: multipart/mixed") {
-			t.Errorf("expected multipart/mixed, got: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), "--testboundary\r\n") {
-			t.Errorf("expected boundary, got: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), "--testboundary--") {
-			t.Errorf("expected end boundary, got: %s", buffer.String())
-		}
-	})
-	t.Run("msgWriter writes a multipart/related message", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t, WithBoundary("testboundary"))
-		message.EmbedFile("testdata/embed.txt")
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		if !strings.Contains(buffer.String(), "Content-Type: multipart/related") {
-			t.Errorf("expected multipart/related, got: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), "--testboundary\r\n") {
-			t.Errorf("expected boundary, got: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), "--testboundary--") {
-			t.Errorf("expected end boundary, got: %s", buffer.String())
-		}
-	})
-	t.Run("msgWriter writes a multipart/alternative message", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t, WithBoundary("testboundary"))
-		message.AddAlternativeString(TypeTextHTML, "<html><body><h1>Testmail</h1></body></html>")
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		if !strings.Contains(buffer.String(), "Content-Type: multipart/alternative") {
-			t.Errorf("expected multipart/alternative, got: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), "--testboundary\r\n") {
-			t.Errorf("expected boundary, got: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), "--testboundary--") {
-			t.Errorf("expected end boundary, got: %s", buffer.String())
-		}
-	})
-	t.Run("msgWriter writes a application/pgp-encrypted message", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t, WithPGPType(PGPEncrypt), WithBoundary("testboundary"))
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		if !strings.Contains(buffer.String(), "Content-Type: multipart/encrypted") {
-			t.Errorf("expected multipart/encrypted, got: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), "--testboundary\r\n") {
-			t.Errorf("expected boundary, got: %s", buffer.String())
-		}
-	})
-	t.Run("msgWriter writes a application/pgp-signature message", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t, WithPGPType(PGPSignature), WithBoundary("testboundary"))
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		if !strings.Contains(buffer.String(), "Content-Type: multipart/signed") {
-			t.Errorf("expected multipart/signed, got: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), "--testboundary\r\n") {
-			t.Errorf("expected boundary, got: %s", buffer.String())
-		}
-	})
-	t.Run("msgWriter should ignore NoPGP", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t, WithBoundary("testboundary"))
-		message.pgptype = 9
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		if !strings.Contains(buffer.String(), "--testboundary\r\n") {
-			t.Errorf("expected boundary, got: %s", buffer.String())
-		}
-	})
-}
-
-func TestMsgWriter_writePreformattedGenHeader(t *testing.T) {
-	t.Run("message with no preformatted headerset", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter := &msgWriter{
-			writer:  buffer,
-			charset: CharsetUTF8,
-			encoder: getEncoder(EncodingQP),
-		}
-		message := testMessage(t)
-		message.SetGenHeaderPreformatted(HeaderContentID, "This is a content id")
-		msgwriter.writeMsg(message)
-		if !strings.Contains(buffer.String(), "Content-ID: This is a content id\r\n") {
-			t.Errorf("expected preformatted header, got: %s", buffer.String())
-		}
-	})
-}
-
-func TestMsgWriter_addFiles(t *testing.T) {
-	msgwriter := &msgWriter{
-		charset: CharsetUTF8,
-		encoder: getEncoder(EncodingQP),
 	}
-	t.Run("message with a single file attached", func(t *testing.T) {
+	if !strings.Contains(ms, `Message-ID: <message@id.com>`) {
-		buffer := bytes.NewBuffer(nil)
+		ea = append(ea, "Message-ID")
-		msgwriter.writer = buffer
-		message := testMessage(t)
-		message.AttachFile("testdata/attachment.txt")
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		switch runtime.GOOS {
-		case "windows":
-			if !strings.Contains(buffer.String(), "VGhpcyBpcyBhIHRlc3QgYXR0YWNobWVudA0K") {
-				t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
-			}
-		default:
-			if !strings.Contains(buffer.String(), "VGhpcyBpcyBhIHRlc3QgYXR0YWNobWVudAo=") {
-				t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
-			}
-		}
-		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment.txt"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
-		}
-		switch runtime.GOOS {
-		case "freebsd":
-			if !strings.Contains(buffer.String(), `Content-Type: application/octet-stream; name="attachment.txt"`) {
-				t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
-			}
-		default:
-			if !strings.Contains(buffer.String(), `Content-Type: text/plain; charset=utf-8; name="attachment.txt"`) {
-				t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
-			}
-		}
-	})
-	t.Run("message with a single file attached no extension", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t)
-		message.AttachFile("testdata/attachment")
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		switch runtime.GOOS {
-		case "windows":
-			if !strings.Contains(buffer.String(), "VGhpcyBpcyBhIHRlc3QgYXR0YWNobWVudA0K") {
-				t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
-			}
-		default:
-			if !strings.Contains(buffer.String(), "VGhpcyBpcyBhIHRlc3QgYXR0YWNobWVudAo=") {
-				t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
-			}
-		}
-		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), `Content-Type: application/octet-stream; name="attachment"`) {
-			t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
-		}
-	})
-	t.Run("message with a single file attached custom content-type", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t)
-		message.AttachFile("testdata/attachment.txt", WithFileContentType(TypeAppOctetStream))
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		switch runtime.GOOS {
-		case "windows":
-			if !strings.Contains(buffer.String(), "VGhpcyBpcyBhIHRlc3QgYXR0YWNobWVudA0K") {
-				t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
-			}
-		default:
-			if !strings.Contains(buffer.String(), "VGhpcyBpcyBhIHRlc3QgYXR0YWNobWVudAo=") {
-				t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
-			}
-		}
-		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment.txt"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), `Content-Type: application/octet-stream; name="attachment.txt"`) {
-			t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
-		}
-	})
-	t.Run("message with a single file attached custom transfer-encoding", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t)
-		message.AttachFile("testdata/attachment.txt", WithFileEncoding(EncodingUSASCII))
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		if !strings.Contains(buffer.String(), "\r\n\r\nThis is a test attachment") {
-			t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment.txt"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
-		}
-		switch runtime.GOOS {
-		case "freebsd":
-			if !strings.Contains(buffer.String(), `Content-Type: application/octet-stream; name="attachment.txt"`) {
-				t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
-			}
-		default:
-			if !strings.Contains(buffer.String(), `Content-Type: text/plain; charset=utf-8; name="attachment.txt"`) {
-				t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
-			}
-		}
-		if !strings.Contains(buffer.String(), `Content-Transfer-Encoding: 7bit`) {
-			t.Errorf("Content-Transfer-Encoding header not found for attachment. Mail: %s", buffer.String())
-		}
-	})
-	t.Run("message with a single file attached custom description", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t)
-		message.AttachFile("testdata/attachment.txt", WithFileDescription("Testdescription"))
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		switch runtime.GOOS {
-		case "windows":
-			if !strings.Contains(buffer.String(), "VGhpcyBpcyBhIHRlc3QgYXR0YWNobWVudA0K") {
-				t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
-			}
-		default:
-			if !strings.Contains(buffer.String(), "VGhpcyBpcyBhIHRlc3QgYXR0YWNobWVudAo=") {
-				t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
-			}
-		}
-		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment.txt"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
-		}
-		switch runtime.GOOS {
-		case "freebsd":
-			if !strings.Contains(buffer.String(), `Content-Type: application/octet-stream; name="attachment.txt"`) {
-				t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
-			}
-		default:
-			if !strings.Contains(buffer.String(), `Content-Type: text/plain; charset=utf-8; name="attachment.txt"`) {
-				t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
-			}
-		}
-		if !strings.Contains(buffer.String(), `Content-Transfer-Encoding: base64`) {
-			t.Errorf("Content-Transfer-Encoding header not found for attachment. Mail: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), `Content-Description: Testdescription`) {
-			t.Errorf("Content-Description header not found for attachment. Mail: %s", buffer.String())
-		}
-	})
-	t.Run("message with attachment but no body part", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t)
-		message.parts = nil
-		message.AttachFile("testdata/attachment.txt")
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		switch runtime.GOOS {
-		case "windows":
-			if !strings.Contains(buffer.String(), "VGhpcyBpcyBhIHRlc3QgYXR0YWNobWVudA0K") {
-				t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
-			}
-		default:
-			if !strings.Contains(buffer.String(), "VGhpcyBpcyBhIHRlc3QgYXR0YWNobWVudAo=") {
-				t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
-			}
-		}
-		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment.txt"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
-		}
-		switch runtime.GOOS {
-		case "freebsd":
-			if !strings.Contains(buffer.String(), `Content-Type: application/octet-stream; name="attachment.txt"`) {
-				t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
-			}
-		default:
-			if !strings.Contains(buffer.String(), `Content-Type: text/plain; charset=utf-8; name="attachment.txt"`) {
-				t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
-			}
-		}
-		if !strings.Contains(buffer.String(), `Content-Transfer-Encoding: base64`) {
-			t.Errorf("Content-Transfer-Encoding header not found for attachment. Mail: %s", buffer.String())
-		}
-	})
-}
-
-func TestMsgWriter_writePart(t *testing.T) {
-	msgwriter := &msgWriter{
-		charset: CharsetUTF8,
-		encoder: getEncoder(EncodingQP),
 	}
-	t.Run("message with no part charset should use default message charset", func(t *testing.T) {
+	if !strings.Contains(ms, `Precedence: bulk`) {
-		buffer := bytes.NewBuffer(nil)
+		ea = append(ea, "Precedence")
-		msgwriter.writer = buffer
-		message := testMessage(t, WithCharset(CharsetUTF7))
-		message.AddAlternativeString(TypeTextPlain, "thisisatest")
-		message.parts[1].charset = ""
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		if !strings.Contains(buffer.String(), "ontent-Type: text/plain; charset=UTF-7\r\n\r\nTestmail") {
-			t.Errorf("part not found in mail message. Mail: %s", buffer.String())
-		}
-		if !strings.Contains(buffer.String(), "ontent-Type: text/plain; charset=UTF-7\r\n\r\nthisisatest") {
-			t.Errorf("part not found in mail message. Mail: %s", buffer.String())
-		}
-	})
-	t.Run("message with parts that have a description", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		message := testMessage(t)
-		message.AddAlternativeString(TypeTextPlain, "thisisatest")
-		message.parts[1].description = "thisisadescription"
-		msgwriter.writeMsg(message)
-		if msgwriter.err != nil {
-			t.Errorf("msgWriter failed to write: %s", msgwriter.err)
-		}
-		if !strings.Contains(buffer.String(), "Content-Description: thisisadescription") {
-			t.Errorf("part description not found in mail message. Mail: %s", buffer.String())
-		}
-	})
-}
-
-func TestMsgWriter_writeString(t *testing.T) {
-	msgwriter := &msgWriter{
-		charset: CharsetUTF8,
-		encoder: getEncoder(EncodingQP),
 	}
-	t.Run("writeString succeeds", func(t *testing.T) {
+	if !strings.Contains(ms, `Subject: This is a subject`) {
-		buffer := bytes.NewBuffer(nil)
+		ea = append(ea, "Subject")
-		msgwriter.writer = buffer
-		msgwriter.writeString("thisisatest")
-		if !strings.EqualFold(buffer.String(), "thisisatest") {
-			t.Errorf("writeString failed, expected: thisisatest got: %s", buffer.String())
-		}
-	})
-	t.Run("writeString fails", func(t *testing.T) {
-		msgwriter.writer = failReadWriteSeekCloser{}
-		msgwriter.writeString("thisisatest")
-		if msgwriter.err == nil {
-			t.Errorf("writeString succeeded, expected error")
-		}
-	})
-	t.Run("writeString on errored writer should return", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		msgwriter.err = errors.New("intentional error")
-		msgwriter.writeString("thisisatest")
-		if !strings.EqualFold(buffer.String(), "") {
-			t.Errorf("writeString succeeded, expected: empty string, got: %s", buffer.String())
-		}
-	})
-}
-
-func TestMsgWriter_writeHeader(t *testing.T) {
-	msgwriter := &msgWriter{
-		charset: CharsetUTF8,
-		encoder: getEncoder(EncodingQP),
 	}
-	t.Run("writeHeader with single value", func(t *testing.T) {
+	if !strings.Contains(ms, `User-Agent: go-mail v`) {
-		buffer := bytes.NewBuffer(nil)
+		ea = append(ea, "User-Agent")
-		msgwriter.writer = buffer
-		msgwriter.writeHeader(HeaderMessageID, "this.is.a.test")
-		if !strings.EqualFold(buffer.String(), "Message-ID: this.is.a.test\r\n") {
-			t.Errorf("writeHeader failed, expected: %s, got: %s", "Message-ID: this.is.a.test",
-				buffer.String())
-		}
-	})
-	t.Run("writeHeader with multiple values", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		msgwriter.writeHeader(HeaderMessageID, "this.is.a.test", "this.as.well")
-		if !strings.EqualFold(buffer.String(), "Message-ID: this.is.a.test, this.as.well\r\n") {
-			t.Errorf("writeHeader failed, expected: %s, got: %s", "Message-ID: this.is.a.test, this.as.well",
-				buffer.String())
-		}
-	})
-	t.Run("writeHeader with no values", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		msgwriter.writeHeader(HeaderMessageID)
-		// While technically it is permitted to have empty headers, it's recommend to omit them if
-		// no value is present. We follow this recommendation.
-		if !strings.EqualFold(buffer.String(), "") {
-			t.Errorf("writeHeader failed, expected: %s, got: %s", "", buffer.String())
-		}
-	})
-	t.Run("writeHeader with very long value", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		msgwriter.writeHeader(HeaderMessageID, strings.Repeat("a", MaxHeaderLength-13), "next-row")
-		want := "Message-ID:\r\n " + strings.Repeat("a", MaxHeaderLength-13) + ",\r\n next-row\r\n"
-		if !strings.EqualFold(buffer.String(), want) {
-			t.Errorf("writeHeader failed, expected: %s, got: %s", want, buffer.String())
-		}
-	})
-}
-
-func TestMsgWriter_writeBody(t *testing.T) {
-	t.Log("We only cover some edge-cases here, most of the functionality is tested already very thoroughly.")
-
-	msgwriter := &msgWriter{
-		charset: CharsetUTF8,
-		encoder: getEncoder(EncodingQP),
 	}
-	t.Run("writeBody on NoEncoding", func(t *testing.T) {
+	if !strings.Contains(ms, `X-Mailer: go-mail v`) {
-		buffer := bytes.NewBuffer(nil)
+		ea = append(ea, "X-Mailer")
-		msgwriter.writer = buffer
+	}
-		message := testMessage(t)
+	if !strings.Contains(ms, `From: "Toni Tester" <test@example.com>`) {
-		msgwriter.writeBody(message.parts[0].writeFunc, NoEncoding)
+		ea = append(ea, "From")
-		if msgwriter.err != nil {
+	}
-			t.Errorf("writeBody failed to write: %s", msgwriter.err)
+	if !strings.Contains(ms, `To: "Toni Receiver" <receiver@example.com>`) {
+		ea = append(ea, "To")
+	}
+	if !strings.Contains(ms, `Content-Type: text/plain; charset=UTF-8`) {
+		ea = append(ea, "Content-Type")
+	}
+	if !strings.Contains(ms, `Content-Transfer-Encoding: quoted-printable`) {
+		ea = append(ea, "Content-Transfer-Encoding")
+	}
+	if !strings.Contains(ms, "\r\n\r\nThis is the body") {
+		ea = append(ea, "Message body")
+	}
+
+	pl := m.GetParts()
+	if len(pl) <= 0 {
+		t.Errorf("expected multiple parts but got none")
+		return
+	}
+	if len(pl) == 2 {
+		ap := pl[1]
+		ap.SetCharset(CharsetISO88591)
+	}
+	buf.Reset()
+	mw.writeMsg(m)
+	ms = buf.String()
+	if !strings.Contains(ms, "\r\n\r\nThis is the alternative body") {
+		ea = append(ea, "Message alternative body")
+	}
+	if !strings.Contains(ms, `Content-Type: text/html; charset=ISO-8859-1`) {
+		ea = append(ea, "alternative body charset")
+	}
+
+	if len(ea) > 0 {
+		em := "writeMsg() failed. The following errors occurred:\n"
+		for e := range ea {
+			em += fmt.Sprintf("* incorrect %q field", ea[e])
 		}
-	})
+		em += fmt.Sprintf("\n\nFull message:\n%s", ms)
-	t.Run("writeBody on NoEncoding fails on write", func(t *testing.T) {
+		t.Error(em)
-		msgwriter.writer = failReadWriteSeekCloser{}
+	}
-		message := testMessage(t)
+}
-		msgwriter.writeBody(message.parts[0].writeFunc, NoEncoding)
+
-		if msgwriter.err == nil {
+// TestMsgWriter_writeMsg_PGP tests the writeMsg method of the msgWriter with PGP types set
-			t.Errorf("writeBody succeeded, expected error")
+func TestMsgWriter_writeMsg_PGP(t *testing.T) {
-		}
+	m := NewMsg(WithPGPType(PGPEncrypt))
-		if !strings.EqualFold(msgwriter.err.Error(), "bodyWriter io.Copy: intentional write failure") {
+	_ = m.From(`"Toni Tester" <test@example.com>`)
-			t.Errorf("expected error: bodyWriter io.Copy: intentional write failure, got: %s", msgwriter.err)
+	_ = m.To(`"Toni Receiver" <receiver@example.com>`)
-		}
+	m.Subject("This is a subject")
-	})
+	m.SetBodyString(TypeTextPlain, "This is the body")
-	t.Run("writeBody on NoEncoding fails on writeFunc", func(t *testing.T) {
+	buf := bytes.Buffer{}
-		buffer := bytes.NewBuffer(nil)
+	mw := &msgWriter{writer: &buf, charset: CharsetUTF8, encoder: mime.QEncoding}
-		msgwriter.writer = buffer
+	mw.writeMsg(m)
-		writeFunc := func(io.Writer) (int64, error) {
+	ms := buf.String()
-			return 0, errors.New("intentional write failure")
+	if !strings.Contains(ms, `encrypted; protocol="application/pgp-encrypted"`) {
-		}
+		t.Errorf("writeMsg failed. Expected PGP encoding header but didn't find it in message output")
-		msgwriter.writeBody(writeFunc, NoEncoding)
+	}
-		if msgwriter.err == nil {
+
-			t.Errorf("writeBody succeeded, expected error")
+	m = NewMsg(WithPGPType(PGPSignature))
-		}
+	_ = m.From(`"Toni Tester" <test@example.com>`)
-		if !strings.EqualFold(msgwriter.err.Error(), "bodyWriter function: intentional write failure") {
+	_ = m.To(`"Toni Receiver" <receiver@example.com>`)
-			t.Errorf("expected error: bodyWriter function: intentional write failure, got: %s", msgwriter.err)
+	m.Subject("This is a subject")
-		}
+	m.SetBodyString(TypeTextPlain, "This is the body")
-	})
+	buf = bytes.Buffer{}
-	t.Run("writeBody Quoted-Printable fails on write", func(t *testing.T) {
+	mw = &msgWriter{writer: &buf, charset: CharsetUTF8, encoder: mime.QEncoding}
-		msgwriter.writer = failReadWriteSeekCloser{}
+	mw.writeMsg(m)
-		message := testMessage(t)
+	ms = buf.String()
-		msgwriter.writeBody(message.parts[0].writeFunc, EncodingQP)
+	if !strings.Contains(ms, `signed; protocol="application/pgp-signature"`) {
-		if msgwriter.err == nil {
+		t.Errorf("writeMsg failed. Expected PGP encoding header but didn't find it in message output")
-			t.Errorf("writeBody succeeded, expected error")
+	}
-		}
-		if !strings.EqualFold(msgwriter.err.Error(), "bodyWriter function: intentional write failure") {
-			t.Errorf("expected error: bodyWriter function: intentional write failure, got: %s", msgwriter.err)
-		}
-	})
-	t.Run("writeBody Quoted-Printable fails on writeFunc", func(t *testing.T) {
-		buffer := bytes.NewBuffer(nil)
-		msgwriter.writer = buffer
-		writeFunc := func(io.Writer) (int64, error) {
-			return 0, errors.New("intentional write failure")
-		}
-		msgwriter.writeBody(writeFunc, EncodingQP)
-		if msgwriter.err == nil {
-			t.Errorf("writeBody succeeded, expected error")
-		}
-		if !strings.EqualFold(msgwriter.err.Error(), "bodyWriter function: intentional write failure") {
-			t.Errorf("expected error: bodyWriter function: intentional write failure, got: %s", msgwriter.err)
-		}
-	})
 }

testdata/attachment

@@ -1 +0,0 @@
-This is a test attachment

testdata/attachment.license

@@ -1,3 +0,0 @@
-// SPDX-FileCopyrightText: Copyright (c) 2022-2024 The go-mail Authors
-//
-// SPDX-License-Identifier: MIT