@Test
public void testConstructionWithNullType() {

    String index = "idx0";
    String id = "00001_AE";
    Map<String, Object> expectedMap = new HashMap<String, Object>();
    expectedMap.put("_index", index);
    expectedMap.put("_id", id);
    Doc doc = new Doc(index, id);
    Map<String, Object> actualMap = doc.toMap();
    assertEquals(2, actualMap.size());
    assertEquals(expectedMap, actualMap);
}