fixed iterator issue under python2

Author: d80tb7

python/pyspark/serializers.py

@@ -373,6 +373,9 @@ def __next__(self):
         batch2 = pa.read_record_batch(self._reader.read_next_message(),  self._schema2)
         return batch1, batch2
 
+    def next(self):
+        return self.__next__()
+
 
 class ArrowStreamPandasUDFSerializer(ArrowStreamPandasSerializer):
     """

python/pyspark/sql/tests/test_pandas_udf_cogrouped_map.py

@@ -90,3 +90,12 @@ def merge_pandas(left, right):
 
         assert_frame_equal(expected, result, check_column_type=_check_column_type)
 
+if __name__ == "__main__":
+    from pyspark.sql.tests.test_pandas_udf_cogrouped_map import *
+
+    try:
+        import xmlrunner
+        testRunner = xmlrunner.XMLTestRunner(output='target/test-reports', verbosity=2)
+    except ImportError:
+        testRunner = None
+    unittest.main(testRunner=testRunner, verbosity=2)