@Test
  public void canSerializeArraysWithNullablePrimitiveElements() throws SerDeException, IOException {
    final String field = "{ \"name\":\"listWithNulls\", \"type\": " +
            "{\"type\":\"array\", \"items\": [\"null\", \"int\"]} }";
    List<Integer> intList = new ArrayList<Integer>();
    Collections.addAll(intList, 1,2, null, 3);
    GenericRecord r = serializeAndDeserialize(field, "listWithNulls", intList);
    Object result = r.get("listWithNulls");
    assertNotSame(intList, result);
    assertEquals(intList, result);
  }
Verify that we can serialize an avro value by taking one, running it through
the deser process and then serialize it again.
serde/src/test/org/apache/hadoop/hive/serde2/avro/TestAvroSerializer.java