@Test
public void isContentExpected() {

    assertTrue(SmtpCommand.valueOf("DATA").isContentExpected());
    assertTrue(SmtpCommand.valueOf("data").isContentExpected());
    assertFalse(SmtpCommand.HELO.isContentExpected());
    assertFalse(SmtpCommand.HELP.isContentExpected());
    assertFalse(SmtpCommand.valueOf("DATA2").isContentExpected());
}