@Test
public void testExtractAuxiliaryData() throws Exception {

    Params meta = new Params().set(SOME_PARAM, "value");
    List<String> stringList = new ArrayList<>();
    stringList.add("apple");
    stringList.add("banana");
    MockCollector collector = new MockCollector();
    ModelConverterUtils.appendMetaRow(meta, collector, 3);
    ModelConverterUtils.appendDataRows(stringList, collector, 3);
    ModelConverterUtils.appendAuxiliaryData(stringList, collector, 3);
    Iterable<Object> labels = ModelConverterUtils.extractAuxiliaryData(collector.buffer, true);
    Iterator<Object> labelIterator = labels.iterator();
    Assert.assertTrue(labelIterator.hasNext());
    Assert.assertEquals(labelIterator.next(), "apple");
    Assert.assertTrue(labelIterator.hasNext());
    Assert.assertEquals(labelIterator.next(), "banana");
}