public void testOrderingBothNull() throws Exception {
assertEquals(0, comparator.compare(null, null));
}
private void assertSmaller(ErrorWithLevel p1, ErrorWithLevel p2) {
int p1p2 = comparator.compare(p1, p2);
assertTrue(Integer.toString(p1p2), p1p2 < 0);
int p2p1 = comparator.compare(p2, p1);
assertTrue(Integer.toString(p2p1), p2p1 > 0);
}