@Test
public void testEquals() {

  assertEquals(new SimpleDate(2013, 5, 10), new SimpleDate(2013, 5, 10));
  assertThat(new SimpleDate(2013, 5, 10)).isNotEqualTo(new SimpleDate(2014, 5, 10));
  assertThat(new SimpleDate(2013, 5, 10)).isNotEqualTo(new SimpleDate(2013, 6, 10));
  assertThat(new SimpleDate(2013, 5, 10)).isNotEqualTo(new SimpleDate(2013, 5, 11));
}