@Test(timeout = 5000)
public void testNonEmpty() throws Exception {

  // InputReader
  final String singleData = "Single";
  final List<String> dataElements = new ArrayList<>(1);
  dataElements.add(singleData); // Single element
  final InputReader inputReader = generateInputReader(generateCompletableFuture(dataElements.iterator()));
  // Fetcher
  final ParentTaskDataFetcher fetcher = createFetcher(inputReader);
  // Should return only a single element
  assertEquals(singleData, fetcher.fetchDataElement());
}