hasZone := zoneOffset != 0
	hasFracSecond := t.Nanosecond() != 0
	hasSecond := t.Second() != 0
	hasTime := t.Hour() != 0 || t.Minute() != 0
	hasDay := t.Day() != 1
	hasMonth := t.Month() != 1

	switch {
	case hasFracSecond:
		return t.Format(layoutNanosecond)
	case hasSecond:
		return t.Format(layoutSecond)
	case hasTime || hasZone:
		return t.Format(layoutMinute)
	case hasDay:
		return t.Format(layoutDay)

	}
}

func Test_metaCacheEntries_resolve(t *testing.T) {
	baseTime, err := time.Parse("2006/01/02", "2015/02/25")
	if err != nil {
		t.Fatal(err)
	}
	inputs := []xlMetaV2{
		0: {
			versions: []xlMetaV2ShallowVersion{
				{header: xlMetaV2VersionHeader{
					VersionID: [16]byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
					ModTime:   baseTime.Add(30 * time.Minute).UnixNano(),
					Signature: [4]byte{1, 1, 1, 1},