assertFunction("date_trunc('day', " + WEIRD_TIMESTAMP_LITERAL + ")", toTimestampWithTimeZone(result));
result = result.withDayOfMonth(20);
assertFunction("date_trunc('week', " + WEIRD_TIMESTAMP_LITERAL + ")", toTimestampWithTimeZone(result));
result = result.withDayOfMonth(1);
assertFunction("date_trunc('month', " + WEIRD_TIMESTAMP_LITERAL + ")", toTimestampWithTimeZone(result));
result = result.withMonthOfYear(7);
assertFunction("date_trunc('quarter', " + WEIRD_TIMESTAMP_LITERAL + ")", toTimestampWithTimeZone(result));