  @Test
  public void noNulls() throws IOException, ParseException {

    ImmutableMap<String, Integer> contigs = ImmutableMap.of("chr1", 0, "chr10", 1, "chr11", 2);
    assertThrows(NullPointerException.class, () -> Position.of(null, 0, contigs));
    assertThrows(NullPointerException.class, () -> Position.of("chr1", 0, null));
  }