@Test // That Union[T, NULL] is converted to just T, within a Map
  public void convertsMapsWithNullablePrimitiveTypes() throws SerDeException {
    Schema s = AvroSerdeUtils.getSchemaFor(MAP_WITH_NULLABLE_PRIMITIVE_VALUE_TYPE_SCHEMA);
    AvroObjectInspectorGenerator aoig = new AvroObjectInspectorGenerator(s);
    verifyMap(aoig, "aMap");
  }
Check a given AvroObjectInspectorGenerator to verify that it matches our test
schema's expected map.
@param aoig should already have been initialized, may not be null
@param fieldName name of the contained column, will always fail if null.
serde/src/test/org/apache/hadoop/hive/serde2/avro/TestAvroObjectInspectorGenerator.java