Add error handling for writing EML string to temp file

Added conditional statements to handle potential failures when writing the EML string to the temporary files during testing. These updates ensure test failures due to write errors are accurately reflected in test results. Also, a minor fix is implemented on file permission in the os.WriteFile function.

eml_test.go

@@ -653,6 +653,9 @@ func TestEMLToMsgFromReaderFailing(t *testing.T) {
 
 func TestEMLToMsgFromFileFailing(t *testing.T) {
 	tempDir, tempFile, err := stringToTempFile(exampleMailPlainBrokenFrom, "testmail")
+	if err != nil {
+		t.Errorf("failed to write EML string to temp file: %s", err)
+	}
 	_, err = EMLToMsgFromFile(tempFile)
 	if err == nil {
 		t.Error("EML from Reader with broken FROM was supposed to fail, but didn't")
@@ -661,6 +664,9 @@ func TestEMLToMsgFromFileFailing(t *testing.T) {
 		t.Error("failed to remove temp dir:", err)
 	}
 	tempDir, tempFile, err = stringToTempFile(exampleMailPlainBrokenHeader, "testmail")
+	if err != nil {
+		t.Errorf("failed to write EML string to temp file: %s", err)
+	}
 	_, err = EMLToMsgFromFile(tempFile)
 	if err == nil {
 		t.Error("EML from Reader with broken header was supposed to fail, but didn't")
@@ -669,6 +675,9 @@ func TestEMLToMsgFromFileFailing(t *testing.T) {
 		t.Error("failed to remove temp dir:", err)
 	}
 	tempDir, tempFile, err = stringToTempFile(exampleMailPlainB64BrokenBody, "testmail")
+	if err != nil {
+		t.Errorf("failed to write EML string to temp file: %s", err)
+	}
 	_, err = EMLToMsgFromFile(tempFile)
 	if err == nil {
 		t.Error("EML from Reader with broken body was supposed to fail, but didn't")
@@ -677,6 +686,9 @@ func TestEMLToMsgFromFileFailing(t *testing.T) {
 		t.Error("failed to remove temp dir:", err)
 	}
 	tempDir, tempFile, err = stringToTempFile(exampleMailPlainBrokenBody, "testmail")
+	if err != nil {
+		t.Errorf("failed to write EML string to temp file: %s", err)
+	}
 	_, err = EMLToMsgFromFile(tempFile)
 	if err == nil {
 		t.Error("EML from Reader with broken body was supposed to fail, but didn't")
@@ -685,6 +697,9 @@ func TestEMLToMsgFromFileFailing(t *testing.T) {
 		t.Error("failed to remove temp dir:", err)
 	}
 	tempDir, tempFile, err = stringToTempFile(exampleMailPlainUnknownContentType, "testmail")
+	if err != nil {
+		t.Errorf("failed to write EML string to temp file: %s", err)
+	}
 	_, err = EMLToMsgFromFile(tempFile)
 	if err == nil {
 		t.Error("EML from Reader with unknown content type was supposed to fail, but didn't")
@@ -693,6 +708,9 @@ func TestEMLToMsgFromFileFailing(t *testing.T) {
 		t.Error("failed to remove temp dir:", err)
 	}
 	tempDir, tempFile, err = stringToTempFile(exampleMailPlainNoContentType, "testmail")
+	if err != nil {
+		t.Errorf("failed to write EML string to temp file: %s", err)
+	}
 	_, err = EMLToMsgFromFile(tempFile)
 	if err == nil {
 		t.Error("EML from Reader with no content type was supposed to fail, but didn't")
@@ -701,6 +719,9 @@ func TestEMLToMsgFromFileFailing(t *testing.T) {
 		t.Error("failed to remove temp dir:", err)
 	}
 	tempDir, tempFile, err = stringToTempFile(exampleMailPlainUnsupportedTransferEnc, "testmail")
+	if err != nil {
+		t.Errorf("failed to write EML string to temp file: %s", err)
+	}
 	_, err = EMLToMsgFromFile(tempFile)
 	if err == nil {
 		t.Error("EML from Reader with unsupported Transer-Encoding was supposed to fail, but didn't")
@@ -852,7 +873,7 @@ func stringToTempFile(data, name string) (string, string, error) {
 		return tempDir, "", fmt.Errorf("failed to create temp dir: %w", err)
 	}
 	filePath := fmt.Sprintf("%s/%s", tempDir, name)
-	err = os.WriteFile(filePath, []byte(data), 0666)
+	err = os.WriteFile(filePath, []byte(data), 0o666)
 	if err != nil {
 		return tempDir, "", fmt.Errorf("failed to write data to temp file: %w", err)
 	}