@Test
public void invalidEmailAddresses() {

    //copied from https://en.wikipedia.org/wiki/Email_address#Examples
    Assert.assertFalse(EmailAddressUtil.isValid("Abc.example.com"));
    Assert.assertFalse(EmailAddressUtil.isValid("A@b@c@example.com"));
    Assert.assertFalse(EmailAddressUtil.isValid("a\"b(c)d,e:f;g<h>i[j\\k]l@example.com"));
    Assert.assertFalse(EmailAddressUtil.isValid("just\"not\"right@example.com"));
    Assert.assertFalse(EmailAddressUtil.isValid("this is\"not\\allowed@example.com"));
    Assert.assertFalse(EmailAddressUtil.isValid("this\\ still\\\"not\\\\allowed@example.com"));
}