public void test_string_conversion() {
    Date d1 = Dates.newDate(2010, 12, 31, 10, 0, 0);
    assertEquals("2010-12-31 10:00:00", Dates.toDbString(d1));

    assertTrue(Dates.equal(d1, Dates.fromDbString("2010-12-31 10:00:00")));

    try {
      Dates.fromDbString("today");
      fail();
    } catch (Exception e) {
      assertEquals("Cannot parse 'today' as date", e.getMessage());
    }
  }