| AddEmbeddedImageTest | Test adding embedded image(s) functionality. |
| AddStringAttachmentTest | Test adding string attachments functionality. |
| AddStringEmbeddedImageTest | Test adding stringified attachments functionality. |
| AuthCRAMMD5Test | Test CRAM-MD5 authentication functionality. |
| CustomHeaderTest | Test custom header functionality. |
| DKIMTest | Test DKIM signing functionality. |
| EncodeQTest | Test encoding a string using Q encoding functionality. |
| EncodeStringTest | Test string encoding functionality. |
| FileIsAccessibleTest | Test file accessibility verification functionality. |
| FilenameToTypeTest | Test file name to type functionality. |
| GenerateIdTest | Test unique ID generation functionality. |
| GetLastMessageIDTest | Test setting and retrieving message ID. |
| HasLineLongerThanMaxTest | Test line length detection and handling. |
| Html2TextTest | Test HTML to text conversion functionality. |
| ICalTest | Test ICal calendar events handling. |
| IsPermittedPathTest | Test path validation functionality. |
| IsValidHostTest | Test host validation functionality. |
| LocalizationTest | Test localized error message functionality. |
| MailTransportTest | Test sending mail using the various available mail transport options. |
| MbPathinfoTest | Test Multi-byte-safe pathinfo replacement functionality. |
| MimeTypesTest | Test mime type mapping functionality. |
| NormalizeBreaksTest | Test normalize line breaks functionality. |
| ParseAddressesTest | Test RFC822 address splitting. |
| PHPMailerTest | PHPMailer - PHP email transport unit test class. |
| PunyencodeAddressTest | Test IDN to ASCII functionality. |
| QuotedStringTest | Test quoted string functionality. |
| ReplyToGetSetClearTest | Test reply-to address setting, getting and clearing functionality. |
| SetErrorTest | Test error registration functionality. |
| SetFromTest | Test setting the "from" address. |
| SetTest | Test property setting functionality. |
| SetWordWrapTest | Test automatic wordwrap functionality. |
| Utf8CharBoundaryTest | Test UTF8 character boundary functionality. |
| ValidateAddressCustomValidatorTest | Test email address validation using a custom validator. |
| ValidateAddressTest | Test email address validation. |
| WrapTextTest | Test word wrapping functionality. |
| XMailerTest | Test XMailer header setting functionality. |