@Test
public void dataSgroupRoundTrip() {

  String path = "/data/mdl/hbr_acoh_mix.mol";
  try (InputStream in = getClass().getResourceAsStream(path)) {
    MDLV2000Reader     mdlr    = new MDLV2000Reader(in);
    IChemObjectBuilder builder = SilentChemObjectBuilder.getInstance();
    IAtomContainer     mol     = mdlr.read(builder.newAtomContainer());
    try (StringWriter sw = new StringWriter();
         MDLV2000Writer writer = new MDLV2000Writer(sw)) {
      writer.write(mol);
      String output = sw.toString();
      assertThat(output,
                 CoreMatchers.containsString("M  SDT   3 WEIGHT_PERCENT                N %"));
      assertThat(output,
                 CoreMatchers.containsString("M  SED   3 33%"));
    }
  } catch (IOException | CDKException e) {
    Assert.fail(e.getMessage());
  }
}