public static Iterable<Snapshot> currentAncestors(Table table) {
    return ancestorsOf(table.currentSnapshot(), table::snapshot);
  }
@Test
  public void currentAncestors() {
    Iterable<Snapshot> snapshots = SnapshotUtil.currentAncestors(table);
    expectedSnapshots(new long[] {snapshotMain2Id, snapshotMain1Id, snapshotBaseId}, snapshots);

    List<Long> snapshotList = SnapshotUtil.currentAncestorIds(table);
    assertThat(snapshotList.toArray(new Long[0]))
        .isEqualTo(new Long[] {snapshotMain2Id, snapshotMain1Id, snapshotBaseId});
  }