#18: Method renaming and tests

- Renamed `Msg.WriteToTempfile` to `Msg.WriteToTempFile`
- Added test coverage for `Msg.WriteToFile` and `Msg.WriteToTempFile`

msg_test.go

@@ -7,6 +7,7 @@ import (
 	htpl "html/template"
 	"io"
 	"net/mail"
+	"os"
 	"strings"
 	"testing"
 	ttpl "text/template"
@@ -1700,3 +1701,43 @@ func TestMsg_EmbedHTMLTemplate(t *testing.T) {
 		})
 	}
 }
+
+// TestMsg_WriteToTempFile will test the output to temporary files
+func TestMsg_WriteToTempFile(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")
+	f, err := m.WriteToTempFile()
+	if err != nil {
+		t.Errorf("failed to write message to temporary output file: %s", err)
+	}
+	_ = os.Remove(f)
+}
+
+// TestMsg_WriteToFile will test the output to a file
+func TestMsg_WriteToFile(t *testing.T) {
+	f, err := os.CreateTemp("", "go-mail-test_*.eml")
+	if err != nil {
+		t.Errorf("failed to create temporary output file: %s", err)
+	}
+	defer func() {
+		_ = f.Close()
+		_ = os.Remove(f.Name())
+	}()
+
+	m := NewMsg()
+	_ = m.From("Toni Tester <tester@example.com>")
+	_ = m.To("Ellenor Tester <ellinor@example.com>")
+	m.SetBodyString(TypeTextPlain, "This is a test")
+	if err := m.WriteToFile(f.Name()); err != nil {
+		t.Errorf("failed to write to output file: %s", err)
+	}
+	fi, err := os.Stat(f.Name())
+	if err != nil {
+		t.Errorf("failed to stat output file: %s", err)
+	}
+	if fi.Size() <= 0 {
+		t.Errorf("output file is expected to contain data but its size is zero")
+	}
+}

msg_totmpfile.go

@@ -8,9 +8,9 @@ import (
 	"os"
 )
 
-// WriteToTempfile will create a temporary file and output the Msg to this file
+// WriteToTempFile will create a temporary file and output the Msg to this file
 // The method will return the filename of the temporary file
-func (m *Msg) WriteToTempfile() (string, error) {
+func (m *Msg) WriteToTempFile() (string, error) {
 	f, err := os.CreateTemp("", "go-mail_*.eml")
 	if err != nil {
 		return "", fmt.Errorf("failed to create output file: %w", err)

msg_totmpfile_116.go

@@ -8,9 +8,9 @@ import (
 	"io/ioutil"
 )
 
-// WriteToTempfile will create a temporary file and output the Msg to this file
+// WriteToTempFile will create a temporary file and output the Msg to this file
 // The method will return the filename of the temporary file
-func (m *Msg) WriteToTempfile() (string, error) {
+func (m *Msg) WriteToTempFile() (string, error) {
 	f, err := ioutil.TempFile("", "go-mail_*.eml")
 	if err != nil {
 		return "", fmt.Errorf("failed to create output file: %w", err)