code: @Test public void testThatMailImplWorksAsExpected(){
    Mail mail=MailImplTestHelper.getMailImplWithDemoContent();
    MailImpl mailImpl=(MailImpl)mail;
    assertTrue(mailImpl.getSubject().equals("subject"));
    assertTrue(mailImpl.getFrom().contains("from1@domain"));
    assertTrue(mailImpl.getReplyTo().contains("replyTo1@domain"));
    assertTrue(mailImpl.getReplyTo().contains("replyTo2@domain"));
    mail.setCharset("utf-8");
    assertTrue(mailImpl.getCharset().contains("utf-8"));
    assertTrue(mailImpl.getHeaders().get("header1").equals("value1"));
    assertTrue(mailImpl.getHeaders().get("header2").equals("value2"));
    assertTrue(mailImpl.getTos().contains("to1@domain"));
    assertTrue(mailImpl.getTos().contains("to2@domain"));
    assertTrue(mailImpl.getCcs().contains("cc1@domain"));
    assertTrue(mailImpl.getCcs().contains("cc2@domain"));
    assertTrue(mailImpl.getBccs().contains("bcc1@domain"));
    assertTrue(mailImpl.getBccs().contains("bcc2@domain"));
    assertTrue(mailImpl.getBodyText().equals("bodyText"));
    assertTrue(mailImpl.getBodyHtml().equals("bodyHtml"));
  }
  