Merge 894936092e into 619318ba0d

2024-11-23 14:10:50 +01:00 · 2024-09-20 11:33:59 +02:00
13 changed files with 45 additions and 842 deletions
--- a/.github/workflows/codecov.yml
+++ b/.github/workflows/codecov.yml
@ -36,7 +36,7 @@ jobs:
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest, windows-latest]
-        go: ['1.19', '1.20', '1.23']
+        go: ['1.20', '1.21', '1.22', '1.23']
    steps:
    - name: Harden Runner
      uses: step-security/harden-runner@91182cccc01eb5e619899d80e4e971d6181294a7 # v2.10.1
--- a/client_119.go
+++ b/client_119.go
@ -7,22 +7,16 @@

 package mail

-import "errors"
-
 // Send sends out the mail message
 func (c *Client) Send(messages ...*Msg) error {
 	if err := c.checkConn(); err != nil {
 		return &SendError{Reason: ErrConnCheck, errlist: []error{err}, isTemp: isTempError(err)}
 	}
 	var errs []*SendError
-	for id, message := range messages {
+	for _, message := range messages {
 		if sendErr := c.sendSingleMsg(message); sendErr != nil {
 			messages[id].sendError = sendErr
-
-			var msgSendErr *SendError
-			if errors.As(sendErr, &msgSendErr) {
-				errs = append(errs, msgSendErr)
-			}
+			errs = append(errs, sendErr)
 		}
 	}

--- a/client_test.go
+++ b/client_test.go
@ -5,7 +5,6 @@
 package mail

 import (
-	"bufio"
 	"context"
 	"crypto/tls"
 	"errors"
@ -22,18 +21,11 @@ import (
 	"github.com/wneessen/go-mail/smtp"
 )

-const (
-	// DefaultHost is used as default hostname for the Client
-	DefaultHost = "localhost"
-	// TestRcpt is a trash mail address to send test mails to
-	TestRcpt = "go-mail@mytrashmailer.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
-	TestServerAddr = "127.0.0.1"
-	// TestServerPortBase is the base port for the simple SMTP test server
-	TestServerPortBase = 2025
-)
+// DefaultHost is used as default hostname for the Client
+const DefaultHost = "localhost"
+
+// TestRcpt
+const TestRcpt = "go-mail@mytrashmailer.com"

 // TestNewClient tests the NewClient() method with its default options
 func TestNewClient(t *testing.T) {
@ -1259,475 +1251,6 @@ func TestClient_DialAndSendWithContext_withSendError(t *testing.T) {
 	}
 }

-func TestClient_SendErrorNoEncoding(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	featureSet := "250-AUTH PLAIN\r\n250-DSN\r\n250 SMTPUTF8"
-	serverPort := TestServerPortBase + 1
-	go func() {
-		if err := simpleSMTPServer(ctx, featureSet, false, serverPort); err != nil {
-			t.Errorf("failed to start test server: %s", err)
-			return
-		}
-	}()
-	time.Sleep(time.Millisecond * 300)
-
-	message := NewMsg()
-	if err := message.From("valid-from@domain.tld"); err != nil {
-		t.Errorf("failed to set FROM address: %s", err)
-		return
-	}
-	if err := message.To("valid-to@domain.tld"); err != nil {
-		t.Errorf("failed to set TO address: %s", err)
-		return
-	}
-	message.Subject("Test subject")
-	message.SetBodyString(TypeTextPlain, "Test body")
-	message.SetMessageIDWithValue("this.is.a.message.id")
-	message.SetEncoding(NoEncoding)
-
-	client, err := NewClient(TestServerAddr, WithPort(serverPort),
-		WithTLSPortPolicy(NoTLS), WithSMTPAuth(SMTPAuthPlain),
-		WithUsername("toni@tester.com"),
-		WithPassword("V3ryS3cr3t+"))
-	if err != nil {
-		t.Errorf("unable to create new client: %s", err)
-	}
-	if err = client.DialWithContext(context.Background()); err != nil {
-		t.Errorf("failed to dial to test server: %s", err)
-	}
-	if err = client.Send(message); err == nil {
-		t.Error("expected Send() to fail but didn't")
-	}
-
-	var sendErr *SendError
-	if !errors.As(err, &sendErr) {
-		t.Errorf("expected *SendError type as returned error, but got %T", sendErr)
-	}
-	if errors.As(err, &sendErr) {
-		if sendErr.IsTemp() {
-			t.Errorf("expected permanent error but IsTemp() returned true")
-		}
-		if sendErr.Reason != ErrNoUnencoded {
-			t.Errorf("expected ErrNoUnencoded error, but got %s", sendErr.Reason)
-		}
-		if !strings.EqualFold(sendErr.MessageID(), "<this.is.a.message.id>") {
-			t.Errorf("expected message ID: %q, but got %q", "<this.is.a.message.id>",
-				sendErr.MessageID())
-		}
-		if sendErr.Msg() == nil {
-			t.Errorf("expected message to be set, but got nil")
-		}
-	}
-
-	if err = client.Close(); err != nil {
-		t.Errorf("failed to close server connection: %s", err)
-	}
-}
-
-func TestClient_SendErrorMailFrom(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	serverPort := TestServerPortBase + 2
-	featureSet := "250-AUTH PLAIN\r\n250-8BITMIME\r\n250-DSN\r\n250 SMTPUTF8"
-	go func() {
-		if err := simpleSMTPServer(ctx, featureSet, false, serverPort); err != nil {
-			t.Errorf("failed to start test server: %s", err)
-			return
-		}
-	}()
-	time.Sleep(time.Millisecond * 300)
-
-	message := NewMsg()
-	if err := message.From("invalid-from@domain.tld"); err != nil {
-		t.Errorf("failed to set FROM address: %s", err)
-		return
-	}
-	if err := message.To("valid-to@domain.tld"); err != nil {
-		t.Errorf("failed to set TO address: %s", err)
-		return
-	}
-	message.Subject("Test subject")
-	message.SetBodyString(TypeTextPlain, "Test body")
-	message.SetMessageIDWithValue("this.is.a.message.id")
-
-	client, err := NewClient(TestServerAddr, WithPort(serverPort),
-		WithTLSPortPolicy(NoTLS), WithSMTPAuth(SMTPAuthPlain),
-		WithUsername("toni@tester.com"),
-		WithPassword("V3ryS3cr3t+"))
-	if err != nil {
-		t.Errorf("unable to create new client: %s", err)
-	}
-	if err = client.DialWithContext(context.Background()); err != nil {
-		t.Errorf("failed to dial to test server: %s", err)
-	}
-	if err = client.Send(message); err == nil {
-		t.Error("expected Send() to fail but didn't")
-	}
-
-	var sendErr *SendError
-	if !errors.As(err, &sendErr) {
-		t.Errorf("expected *SendError type as returned error, but got %T", sendErr)
-	}
-	if errors.As(err, &sendErr) {
-		if sendErr.IsTemp() {
-			t.Errorf("expected permanent error but IsTemp() returned true")
-		}
-		if sendErr.Reason != ErrSMTPMailFrom {
-			t.Errorf("expected ErrSMTPMailFrom error, but got %s", sendErr.Reason)
-		}
-		if !strings.EqualFold(sendErr.MessageID(), "<this.is.a.message.id>") {
-			t.Errorf("expected message ID: %q, but got %q", "<this.is.a.message.id>",
-				sendErr.MessageID())
-		}
-		if sendErr.Msg() == nil {
-			t.Errorf("expected message to be set, but got nil")
-		}
-	}
-
-	if err = client.Close(); err != nil {
-		t.Errorf("failed to close server connection: %s", err)
-	}
-}
-
-func TestClient_SendErrorMailFromReset(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	serverPort := TestServerPortBase + 3
-	featureSet := "250-AUTH PLAIN\r\n250-8BITMIME\r\n250-DSN\r\n250 SMTPUTF8"
-	go func() {
-		if err := simpleSMTPServer(ctx, featureSet, true, serverPort); err != nil {
-			t.Errorf("failed to start test server: %s", err)
-			return
-		}
-	}()
-	time.Sleep(time.Millisecond * 300)
-
-	message := NewMsg()
-	if err := message.From("invalid-from@domain.tld"); err != nil {
-		t.Errorf("failed to set FROM address: %s", err)
-		return
-	}
-	if err := message.To("valid-to@domain.tld"); err != nil {
-		t.Errorf("failed to set TO address: %s", err)
-		return
-	}
-	message.Subject("Test subject")
-	message.SetBodyString(TypeTextPlain, "Test body")
-	message.SetMessageIDWithValue("this.is.a.message.id")
-
-	client, err := NewClient(TestServerAddr, WithPort(serverPort),
-		WithTLSPortPolicy(NoTLS), WithSMTPAuth(SMTPAuthPlain),
-		WithUsername("toni@tester.com"),
-		WithPassword("V3ryS3cr3t+"))
-	if err != nil {
-		t.Errorf("unable to create new client: %s", err)
-	}
-	if err = client.DialWithContext(context.Background()); err != nil {
-		t.Errorf("failed to dial to test server: %s", err)
-	}
-	if err = client.Send(message); err == nil {
-		t.Error("expected Send() to fail but didn't")
-	}
-
-	var sendErr *SendError
-	if !errors.As(err, &sendErr) {
-		t.Errorf("expected *SendError type as returned error, but got %T", sendErr)
-	}
-	if errors.As(err, &sendErr) {
-		if sendErr.IsTemp() {
-			t.Errorf("expected permanent error but IsTemp() returned true")
-		}
-		if sendErr.Reason != ErrSMTPMailFrom {
-			t.Errorf("expected ErrSMTPMailFrom error, but got %s", sendErr.Reason)
-		}
-		if !strings.EqualFold(sendErr.MessageID(), "<this.is.a.message.id>") {
-			t.Errorf("expected message ID: %q, but got %q", "<this.is.a.message.id>",
-				sendErr.MessageID())
-		}
-		if len(sendErr.errlist) != 2 {
-			t.Errorf("expected 2 errors, but got %d", len(sendErr.errlist))
-			return
-		}
-		if !strings.EqualFold(sendErr.errlist[0].Error(), "503 5.1.2 Invalid from: <invalid-from@domain.tld>") {
-			t.Errorf("expected error: %q, but got %q",
-				"503 5.1.2 Invalid from: <invalid-from@domain.tld>", sendErr.errlist[0].Error())
-		}
-		if !strings.EqualFold(sendErr.errlist[1].Error(), "500 5.1.2 Error: reset failed") {
-			t.Errorf("expected error: %q, but got %q",
-				"500 5.1.2 Error: reset failed", sendErr.errlist[1].Error())
-		}
-	}
-
-	if err = client.Close(); err != nil {
-		t.Errorf("failed to close server connection: %s", err)
-	}
-}
-
-func TestClient_SendErrorToReset(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	serverPort := TestServerPortBase + 4
-	featureSet := "250-AUTH PLAIN\r\n250-8BITMIME\r\n250-DSN\r\n250 SMTPUTF8"
-	go func() {
-		if err := simpleSMTPServer(ctx, featureSet, true, serverPort); err != nil {
-			t.Errorf("failed to start test server: %s", err)
-			return
-		}
-	}()
-	time.Sleep(time.Millisecond * 300)
-
-	message := NewMsg()
-	if err := message.From("valid-from@domain.tld"); err != nil {
-		t.Errorf("failed to set FROM address: %s", err)
-		return
-	}
-	if err := message.To("invalid-to@domain.tld"); err != nil {
-		t.Errorf("failed to set TO address: %s", err)
-		return
-	}
-	message.Subject("Test subject")
-	message.SetBodyString(TypeTextPlain, "Test body")
-	message.SetMessageIDWithValue("this.is.a.message.id")
-
-	client, err := NewClient(TestServerAddr, WithPort(serverPort),
-		WithTLSPortPolicy(NoTLS), WithSMTPAuth(SMTPAuthPlain),
-		WithUsername("toni@tester.com"),
-		WithPassword("V3ryS3cr3t+"))
-	if err != nil {
-		t.Errorf("unable to create new client: %s", err)
-	}
-	if err = client.DialWithContext(context.Background()); err != nil {
-		t.Errorf("failed to dial to test server: %s", err)
-	}
-	if err = client.Send(message); err == nil {
-		t.Error("expected Send() to fail but didn't")
-	}
-
-	var sendErr *SendError
-	if !errors.As(err, &sendErr) {
-		t.Errorf("expected *SendError type as returned error, but got %T", sendErr)
-	}
-	if errors.As(err, &sendErr) {
-		if sendErr.IsTemp() {
-			t.Errorf("expected permanent error but IsTemp() returned true")
-		}
-		if sendErr.Reason != ErrSMTPRcptTo {
-			t.Errorf("expected ErrSMTPRcptTo error, but got %s", sendErr.Reason)
-		}
-		if !strings.EqualFold(sendErr.MessageID(), "<this.is.a.message.id>") {
-			t.Errorf("expected message ID: %q, but got %q", "<this.is.a.message.id>",
-				sendErr.MessageID())
-		}
-		if len(sendErr.errlist) != 2 {
-			t.Errorf("expected 2 errors, but got %d", len(sendErr.errlist))
-			return
-		}
-		if !strings.EqualFold(sendErr.errlist[0].Error(), "500 5.1.2 Invalid to: <invalid-to@domain.tld>") {
-			t.Errorf("expected error: %q, but got %q",
-				"500 5.1.2 Invalid to: <invalid-to@domain.tld>", sendErr.errlist[0].Error())
-		}
-		if !strings.EqualFold(sendErr.errlist[1].Error(), "500 5.1.2 Error: reset failed") {
-			t.Errorf("expected error: %q, but got %q",
-				"500 5.1.2 Error: reset failed", sendErr.errlist[1].Error())
-		}
-	}
-
-	if err = client.Close(); err != nil {
-		t.Errorf("failed to close server connection: %s", err)
-	}
-}
-
-func TestClient_SendErrorDataClose(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	serverPort := TestServerPortBase + 5
-	featureSet := "250-AUTH PLAIN\r\n250-8BITMIME\r\n250-DSN\r\n250 SMTPUTF8"
-	go func() {
-		if err := simpleSMTPServer(ctx, featureSet, false, serverPort); err != nil {
-			t.Errorf("failed to start test server: %s", err)
-			return
-		}
-	}()
-	time.Sleep(time.Millisecond * 300)
-
-	message := NewMsg()
-	if err := message.From("valid-from@domain.tld"); err != nil {
-		t.Errorf("failed to set FROM address: %s", err)
-		return
-	}
-	if err := message.To("valid-to@domain.tld"); err != nil {
-		t.Errorf("failed to set TO address: %s", err)
-		return
-	}
-	message.Subject("Test subject")
-	message.SetBodyString(TypeTextPlain, "DATA close should fail")
-	message.SetMessageIDWithValue("this.is.a.message.id")
-
-	client, err := NewClient(TestServerAddr, WithPort(serverPort),
-		WithTLSPortPolicy(NoTLS), WithSMTPAuth(SMTPAuthPlain),
-		WithUsername("toni@tester.com"),
-		WithPassword("V3ryS3cr3t+"))
-	if err != nil {
-		t.Errorf("unable to create new client: %s", err)
-	}
-	if err = client.DialWithContext(context.Background()); err != nil {
-		t.Errorf("failed to dial to test server: %s", err)
-	}
-	if err = client.Send(message); err == nil {
-		t.Error("expected Send() to fail but didn't")
-	}
-
-	var sendErr *SendError
-	if !errors.As(err, &sendErr) {
-		t.Errorf("expected *SendError type as returned error, but got %T", sendErr)
-	}
-	if errors.As(err, &sendErr) {
-		if sendErr.IsTemp() {
-			t.Errorf("expected permanent error but IsTemp() returned true")
-		}
-		if sendErr.Reason != ErrSMTPDataClose {
-			t.Errorf("expected ErrSMTPDataClose error, but got %s", sendErr.Reason)
-		}
-		if !strings.EqualFold(sendErr.MessageID(), "<this.is.a.message.id>") {
-			t.Errorf("expected message ID: %q, but got %q", "<this.is.a.message.id>",
-				sendErr.MessageID())
-		}
-	}
-
-	if err = client.Close(); err != nil {
-		t.Errorf("failed to close server connection: %s", err)
-	}
-}
-
-func TestClient_SendErrorDataWrite(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	serverPort := TestServerPortBase + 6
-	featureSet := "250-AUTH PLAIN\r\n250-8BITMIME\r\n250-DSN\r\n250 SMTPUTF8"
-	go func() {
-		if err := simpleSMTPServer(ctx, featureSet, false, serverPort); err != nil {
-			t.Errorf("failed to start test server: %s", err)
-			return
-		}
-	}()
-	time.Sleep(time.Millisecond * 300)
-
-	message := NewMsg()
-	if err := message.From("valid-from@domain.tld"); err != nil {
-		t.Errorf("failed to set FROM address: %s", err)
-		return
-	}
-	if err := message.To("valid-to@domain.tld"); err != nil {
-		t.Errorf("failed to set TO address: %s", err)
-		return
-	}
-	message.Subject("Test subject")
-	message.SetBodyString(TypeTextPlain, "DATA write should fail")
-	message.SetMessageIDWithValue("this.is.a.message.id")
-	message.SetGenHeader("X-Test-Header", "DATA write should fail")
-
-	client, err := NewClient(TestServerAddr, WithPort(serverPort),
-		WithTLSPortPolicy(NoTLS), WithSMTPAuth(SMTPAuthPlain),
-		WithUsername("toni@tester.com"),
-		WithPassword("V3ryS3cr3t+"))
-	if err != nil {
-		t.Errorf("unable to create new client: %s", err)
-	}
-	if err = client.DialWithContext(context.Background()); err != nil {
-		t.Errorf("failed to dial to test server: %s", err)
-	}
-	if err = client.Send(message); err == nil {
-		t.Error("expected Send() to fail but didn't")
-	}
-
-	var sendErr *SendError
-	if !errors.As(err, &sendErr) {
-		t.Errorf("expected *SendError type as returned error, but got %T", sendErr)
-	}
-	if errors.As(err, &sendErr) {
-		if sendErr.IsTemp() {
-			t.Errorf("expected permanent error but IsTemp() returned true")
-		}
-		if sendErr.Reason != ErrSMTPDataClose {
-			t.Errorf("expected ErrSMTPDataClose error, but got %s", sendErr.Reason)
-		}
-		if !strings.EqualFold(sendErr.MessageID(), "<this.is.a.message.id>") {
-			t.Errorf("expected message ID: %q, but got %q", "<this.is.a.message.id>",
-				sendErr.MessageID())
-		}
-	}
-}
-
-func TestClient_SendErrorReset(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	serverPort := TestServerPortBase + 7
-	featureSet := "250-AUTH PLAIN\r\n250-8BITMIME\r\n250-DSN\r\n250 SMTPUTF8"
-	go func() {
-		if err := simpleSMTPServer(ctx, featureSet, true, serverPort); err != nil {
-			t.Errorf("failed to start test server: %s", err)
-			return
-		}
-	}()
-	time.Sleep(time.Millisecond * 300)
-
-	message := NewMsg()
-	if err := message.From("valid-from@domain.tld"); err != nil {
-		t.Errorf("failed to set FROM address: %s", err)
-		return
-	}
-	if err := message.To("valid-to@domain.tld"); err != nil {
-		t.Errorf("failed to set TO address: %s", err)
-		return
-	}
-	message.Subject("Test subject")
-	message.SetBodyString(TypeTextPlain, "Test body")
-	message.SetMessageIDWithValue("this.is.a.message.id")
-
-	client, err := NewClient(TestServerAddr, WithPort(serverPort),
-		WithTLSPortPolicy(NoTLS), WithSMTPAuth(SMTPAuthPlain),
-		WithUsername("toni@tester.com"),
-		WithPassword("V3ryS3cr3t+"))
-	if err != nil {
-		t.Errorf("unable to create new client: %s", err)
-	}
-	if err = client.DialWithContext(context.Background()); err != nil {
-		t.Errorf("failed to dial to test server: %s", err)
-	}
-	if err = client.Send(message); err == nil {
-		t.Error("expected Send() to fail but didn't")
-	}
-
-	var sendErr *SendError
-	if !errors.As(err, &sendErr) {
-		t.Errorf("expected *SendError type as returned error, but got %T", sendErr)
-	}
-	if errors.As(err, &sendErr) {
-		if sendErr.IsTemp() {
-			t.Errorf("expected permanent error but IsTemp() returned true")
-		}
-		if sendErr.Reason != ErrSMTPReset {
-			t.Errorf("expected ErrSMTPReset error, but got %s", sendErr.Reason)
-		}
-		if !strings.EqualFold(sendErr.MessageID(), "<this.is.a.message.id>") {
-			t.Errorf("expected message ID: %q, but got %q", "<this.is.a.message.id>",
-				sendErr.MessageID())
-		}
-	}
-
-	if err = client.Close(); err != nil {
-		t.Errorf("failed to close server connection: %s", err)
-	}
-}
-
 // getTestConnection takes environment variables to establish a connection to a real
 // SMTP server to test all functionality that requires a connection
 func getTestConnection(auth bool) (*Client, error) {
@ -2022,155 +1545,3 @@ func (f faker) RemoteAddr() net.Addr             { return nil }
 func (f faker) SetDeadline(time.Time) error      { return nil }
 func (f faker) SetReadDeadline(time.Time) error  { return nil }
 func (f faker) SetWriteDeadline(time.Time) error { return nil }
-
-// simpleSMTPServer starts a simple TCP server that resonds to SMTP commands.
-// The provided featureSet represents in what the server responds to EHLO command
-// failReset controls if a RSET succeeds
-func simpleSMTPServer(ctx context.Context, featureSet string, failReset bool, port int) error {
-	listener, err := net.Listen(TestServerProto, fmt.Sprintf("%s:%d", TestServerAddr, port))
-	if err != nil {
-		return fmt.Errorf("unable to listen on %s://%s: %w", TestServerProto, TestServerAddr, err)
-	}
-
-	defer func() {
-		if err := listener.Close(); err != nil {
-			fmt.Printf("unable to close listener: %s\n", err)
-			os.Exit(1)
-		}
-	}()
-
-	for {
-		select {
-		case <-ctx.Done():
-			return nil
-		default:
-			connection, err := listener.Accept()
-			var opErr *net.OpError
-			if err != nil {
-				if errors.As(err, &opErr) && opErr.Temporary() {
-					continue
-				}
-				return fmt.Errorf("unable to accept connection: %w", err)
-			}
-			handleTestServerConnection(connection, featureSet, failReset)
-		}
-	}
-}
-
-func handleTestServerConnection(connection net.Conn, featureSet string, failReset bool) {
-	defer func() {
-		if err := connection.Close(); err != nil {
-			fmt.Printf("unable to close connection: %s\n", err)
-		}
-	}()
-
-	reader := bufio.NewReader(connection)
-	writer := bufio.NewWriter(connection)
-
-	writeLine := func(data string) error {
-		_, err := writer.WriteString(data + "\r\n")
-		if err != nil {
-			return fmt.Errorf("unable to write line: %w", err)
-		}
-		return writer.Flush()
-	}
-	writeOK := func() {
-		_ = writeLine("250 2.0.0 OK")
-	}
-
-	if err := writeLine("220 go-mail test server ready ESMTP"); err != nil {
-		fmt.Printf("unable to write to client: %s\n", err)
-		return
-	}
-
-	data, err := reader.ReadString('\n')
-	if err != nil {
-		fmt.Printf("unable to read from connection: %s\n", err)
-		return
-	}
-	if !strings.HasPrefix(data, "EHLO") && !strings.HasPrefix(data, "HELO") {
-		fmt.Printf("expected EHLO, got %q", data)
-		return
-	}
-	if err = writeLine("250-localhost.localdomain\r\n" + featureSet); err != nil {
-		fmt.Printf("unable to write to connection: %s\n", err)
-		return
-	}
-
-	for {
-		data, err = reader.ReadString('\n')
-		if err != nil {
-			if errors.Is(err, io.EOF) {
-				break
-			}
-			fmt.Println("Error reading data:", err)
-			break
-		}
-
-		var datastring string
-		data = strings.TrimSpace(data)
-		switch {
-		case strings.HasPrefix(data, "MAIL FROM:"):
-			from := strings.TrimPrefix(data, "MAIL FROM:")
-			from = strings.ReplaceAll(from, "BODY=8BITMIME", "")
-			from = strings.ReplaceAll(from, "SMTPUTF8", "")
-			from = strings.TrimSpace(from)
-			if !strings.EqualFold(from, "<valid-from@domain.tld>") {
-				_ = writeLine(fmt.Sprintf("503 5.1.2 Invalid from: %s", from))
-				break
-			}
-			writeOK()
-		case strings.HasPrefix(data, "RCPT TO:"):
-			to := strings.TrimPrefix(data, "RCPT TO:")
-			to = strings.TrimSpace(to)
-			if !strings.EqualFold(to, "<valid-to@domain.tld>") {
-				_ = writeLine(fmt.Sprintf("500 5.1.2 Invalid to: %s", to))
-				break
-			}
-			writeOK()
-		case strings.HasPrefix(data, "AUTH PLAIN"):
-			auth := strings.TrimPrefix(data, "AUTH PLAIN ")
-			if !strings.EqualFold(auth, "AHRvbmlAdGVzdGVyLmNvbQBWM3J5UzNjcjN0Kw==") {
-				_ = writeLine("535 5.7.8 Error: authentication failed")
-				break
-			}
-			_ = writeLine("235 2.7.0 Authentication successful")
-		case strings.EqualFold(data, "DATA"):
-			_ = writeLine("354 End data with <CR><LF>.<CR><LF>")
-			for {
-				ddata, derr := reader.ReadString('\n')
-				if derr != nil {
-					fmt.Printf("failed to read DATA data from connection: %s\n", derr)
-					break
-				}
-				ddata = strings.TrimSpace(ddata)
-				if strings.EqualFold(ddata, "DATA write should fail") {
-					_ = writeLine("500 5.0.0 Error during DATA transmission")
-					break
-				}
-				if ddata == "." {
-					if strings.Contains(datastring, "DATA close should fail") {
-						_ = writeLine("500 5.0.0 Error during DATA closing")
-						break
-					}
-					_ = writeLine("250 2.0.0 Ok: queued as 1234567890")
-					break
-				}
-				datastring += ddata + "\n"
-			}
-		case strings.EqualFold(data, "noop"),
-			strings.EqualFold(data, "vrfy"):
-			writeOK()
-		case strings.EqualFold(data, "rset"):
-			if failReset {
-				_ = writeLine("500 5.1.2 Error: reset failed")
-				break
-			}
-			writeOK()
-		case strings.EqualFold(data, "quit"):
-			_ = writeLine("221 2.0.0 Bye")
-		default:
-			_ = writeLine("500 5.5.2 Error: bad syntax")
-		}
-	}
-}
--- a/msg.go
+++ b/msg.go
@ -482,8 +482,8 @@ func (m *Msg) SetMessageID() {
 	if err != nil {
 		hostname = "localhost.localdomain"
 	}
-	randNumPrimary := randNum(100000000)
-	randNumSecondary := randNum(10000)
+	randNumPrimary, _ := randNum(100000000)
+	randNumSecondary, _ := randNum(10000)
 	randString, _ := randomStringSecure(17)
 	procID := os.Getpid() * randNumSecondary
 	messageID := fmt.Sprintf("%d.%d%d.%s@%s", procID, randNumPrimary, randNumSecondary,
--- a/msg_nowin_test.go
+++ b/msg_nowin_test.go
@ -61,25 +61,3 @@ func TestMsg_WriteToSendmail(t *testing.T) {
 		t.Errorf("WriteToSendmail failed: %s", err)
 	}
 }
-
-func TestMsg_WriteToTempFileFailed(t *testing.T) {
-	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")
-	}
-}
--- a/msg_test.go
+++ b/msg_test.go
@ -786,11 +786,13 @@ func TestMsg_SetMessageIDWithValue(t *testing.T) {
 // TestMsg_SetMessageIDRandomness tests the randomness of Msg.SetMessageID methods
 func TestMsg_SetMessageIDRandomness(t *testing.T) {
 	var mids []string
-	for i := 0; i < 50_000; i++ {
+	for i := 0; i < 100; i++ {
 		m := NewMsg()
 		m.SetMessageID()
-		mid := m.GetMessageID()
-		mids = append(mids, mid)
+		mid := m.GetGenHeader(HeaderMessageID)
+		if len(mid) > 0 {
+			mids = append(mids, mid[0])
+		}
 	}
 	c := make(map[string]int)
 	for i := range mids {
--- a/random.go
+++ b/random.go
@ -7,6 +7,8 @@ package mail
 import (
 	"crypto/rand"
 	"encoding/binary"
+	"fmt"
+	"math/big"
 	"strings"
 )

@ -50,3 +52,23 @@ func randomStringSecure(length int) (string, error) {

 	return randString.String(), nil
 }
+
+// randNum returns a random number with a maximum value of length
+func randNum(length int) (int, error) {
+	if length <= 0 {
+		return 0, fmt.Errorf("provided number is <= 0: %d", length)
+	}
+	length64 := big.NewInt(int64(length))
+	if !length64.IsUint64() {
+		return 0, fmt.Errorf("big.NewInt() generation returned negative value: %d", length64)
+	}
+	randNum64, err := rand.Int(rand.Reader, length64)
+	if err != nil {
+		return 0, err
+	}
+	randomNum := int(randNum64.Int64())
+	if randomNum < 0 {
+		return 0, fmt.Errorf("generated random number does not fit as int64: %d", randNum64)
+	}
+	return randomNum, nil
+}
--- a/random_119.go
+++ b/random_119.go
@ -1,22 +0,0 @@
-// SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
-//
-// SPDX-License-Identifier: MIT
-
-//go:build go1.19 && !go1.20
-// +build go1.19,!go1.20
-
-package mail
-
-import (
-	"math/rand"
-	"time"
-)
-
-// randNum returns a random number with a maximum value of length
-func randNum(maxval int) int {
-	if maxval <= 0 {
-		return 0
-	}
-	rand.Seed(time.Now().UnixNano())
-	return rand.Intn(maxval)
-}
--- a/random_121.go
+++ b/random_121.go
@ -1,20 +0,0 @@
-// SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
-//
-// SPDX-License-Identifier: MIT
-
-//go:build go1.20 && !go1.22
-// +build go1.20,!go1.22
-
-package mail
-
-import (
-	"math/rand"
-)
-
-// randNum returns a random number with a maximum value of length
-func randNum(maxval int) int {
-	if maxval <= 0 {
-		return 0
-	}
-	return rand.Intn(maxval)
-}
--- a/random_122.go
+++ b/random_122.go
@ -1,22 +0,0 @@
-// SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
-//
-// SPDX-License-Identifier: MIT
-
-//go:build go1.22
-// +build go1.22
-
-package mail
-
-import (
-	"math/rand/v2"
-)
-
-// randNum returns a random number with a maximum value of maxval.
-// go-mail compiled with Go 1.22+ will make use of the novel math/rand/v2 interface
-// Older versions of Go will use math/rand
-func randNum(maxval int) int {
-	if maxval <= 0 {
-		return 0
-	}
-	return rand.IntN(maxval)
-}
--- a/random_test.go
+++ b/random_test.go
@ -55,17 +55,16 @@ func TestRandomNum(t *testing.T) {

 	for _, tc := range tt {
 		t.Run(tc.testName, func(t *testing.T) {
-			rn := randNum(tc.max)
+			rn, err := randNum(tc.max)
+			if err != nil {
+				t.Errorf("random number generation failed: %s", err)
+			}
+			if rn < 0 {
+				t.Errorf("random number generation failed: %d is smaller than zero", rn)
+			}
 			if rn > tc.max {
 				t.Errorf("random number generation failed: %d is bigger than given value %d", rn, tc.max)
 			}
 		})
 	}
 }
-
-func TestRandomNumZero(t *testing.T) {
-	rn := randNum(0)
-	if rn != 0 {
-		t.Errorf("random number generation failed: %d is not zero", rn)
-	}
-}
--- a/senderror.go
+++ b/senderror.go
@ -118,23 +118,6 @@ func (e *SendError) IsTemp() bool {
 	return e.isTemp
 }

-// MessageID returns the message ID of the affected Msg that caused the error
-// If no message ID was set for the Msg, an empty string will be returned
-func (e *SendError) MessageID() string {
-	if e == nil || e.affectedMsg == nil {
-		return ""
-	}
-	return e.affectedMsg.GetMessageID()
-}
-
-// Msg returns the pointer to the affected message that caused the error
-func (e *SendError) Msg() *Msg {
-	if e == nil || e.affectedMsg == nil {
-		return nil
-	}
-	return e.affectedMsg
-}
-
 // String implements the Stringer interface for the SendErrReason
 func (r SendErrReason) String() string {
 	switch r {
--- a/senderror_test.go
+++ b/senderror_test.go
@ -90,89 +90,7 @@ func TestSendError_IsTempNil(t *testing.T) {
 	}
 }

-func TestSendError_MessageID(t *testing.T) {
-	var se *SendError
-	err := returnSendError(ErrAmbiguous, false)
-	if !errors.As(err, &se) {
-		t.Errorf("error mismatch, expected error to be of type *SendError")
-		return
-	}
-	if errors.As(err, &se) {
-		if se.MessageID() == "" {
-			t.Errorf("sendError expected message-id, but got empty string")
-		}
-		if !strings.EqualFold(se.MessageID(), "<this.is.a.message.id>") {
-			t.Errorf("sendError message-id expected: %s, but got: %s", "<this.is.a.message.id>",
-				se.MessageID())
-		}
-	}
-}
-
-func TestSendError_MessageIDNil(t *testing.T) {
-	var se *SendError
-	if se.MessageID() != "" {
-		t.Error("expected empty string on nil-senderror")
-	}
-}
-
-func TestSendError_Msg(t *testing.T) {
-	var se *SendError
-	err := returnSendError(ErrAmbiguous, false)
-	if !errors.As(err, &se) {
-		t.Errorf("error mismatch, expected error to be of type *SendError")
-		return
-	}
-	if errors.As(err, &se) {
-		if se.Msg() == nil {
-			t.Errorf("sendError expected msg pointer, but got nil")
-		}
-		from := se.Msg().GetFromString()
-		if len(from) == 0 {
-			t.Errorf("sendError expected msg from, but got empty string")
-			return
-		}
-		if !strings.EqualFold(from[0], "<toni.tester@domain.tld>") {
-			t.Errorf("sendError message from expected: %s, but got: %s", "<toni.tester@domain.tld>",
-				from[0])
-		}
-	}
-}
-
-func TestSendError_MsgNil(t *testing.T) {
-	var se *SendError
-	if se.Msg() != nil {
-		t.Error("expected nil on nil-senderror")
-	}
-}
-
-func TestSendError_IsFail(t *testing.T) {
-	err1 := returnSendError(ErrAmbiguous, false)
-	err2 := returnSendError(ErrSMTPMailFrom, false)
-	if errors.Is(err1, err2) {
-		t.Errorf("error mismatch, ErrAmbiguous should not be equal to ErrSMTPMailFrom")
-	}
-}
-
-func TestSendError_ErrorMulti(t *testing.T) {
-	expected := `ambiguous reason, check Msg.SendError for message specific reasons, ` +
-		`affected recipient(s): <email1@domain.tld>, <email2@domain.tld>`
-	err := &SendError{
-		Reason: ErrAmbiguous, isTemp: false, affectedMsg: nil,
-		rcpt: []string{"<email1@domain.tld>", "<email2@domain.tld>"},
-	}
-	if err.Error() != expected {
-		t.Errorf("error mismatch, expected: %s, got: %s", expected, err.Error())
-	}
-}
-
 // returnSendError is a helper method to retunr a SendError with a specific reason
 func returnSendError(r SendErrReason, t bool) error {
-	message := NewMsg()
-	_ = message.From("toni.tester@domain.tld")
-	_ = message.To("tina.tester@domain.tld")
-	message.Subject("This is the subject")
-	message.SetBodyString(TypeTextPlain, "This is the message body")
-	message.SetMessageIDWithValue("this.is.a.message.id")
-
-	return &SendError{Reason: r, isTemp: t, affectedMsg: message}
+	return &SendError{Reason: r, isTemp: t}
 }