MailClient { public void send(String message, String customerEmail) throws MessagingException { Transport.send(prepareMessage(message, customerEmail)); }  void send(String message, String customerEmail);  }
@Test(expected = MessagingException.class) public void youCannotSendAMailUsingGmailWithAnEmptyUsernameAndPass() throws Exception { MailClient mailClient = new MailClient(); mailClient.send("Test", "oose@gmail.com"); }