@Test
public void testUnmappableKerberosNames() {

    KerberosUserMapper mapper = new KerberosUserMapper();
    try {
        mapper.map("alice@BLAH.NET");
        fail();
    } catch (IllegalArgumentException e) {}
    try {
        mapper.map("@EXAMPLE.COM");
        fail();
    } catch (IllegalArgumentException e) {}
    try {
        mapper.map("@");
        fail();
    } catch (IllegalArgumentException e) {}
}