// to
// Thu Mar 19 7:56:35 PST 2016
var addDateTests = []struct {
	years, months, days int
}{
	{4, 4, 1},
	{3, 16, 1},
	{3, 15, 30},
	{5, -6, -18 - 30 - 12},
}

func TestAddDate(t *testing.T) {
	t0 := Date(2011, 11, 18, 7, 56, 35, 0, UTC)
	t1 := Date(2016, 3, 19, 7, 56, 35, 0, UTC)
	for _, at := range addDateTests {
		time := t0.AddDate(at.years, at.months, at.days)
		if !time.Equal(t1) {