@Test
public void testRoleOverwriteDenies() {

    PermissionSet base = PermissionSet.of(SEND_MESSAGES);
    List<PermissionOverwrite> roleOverwrites = Collections.singletonList(overwrite(PermissionSet.none(), PermissionSet.of(SEND_MESSAGES)));
    PermissionSet actual = PermissionUtil.computePermissions(base, null, roleOverwrites, null);
    PermissionSet expected = PermissionSet.none();
    assertEquals(expected, actual);
}