fix tests in python3

Author: Davies Liu

python/pyspark/shuffle.py

@@ -513,7 +513,7 @@ def load(f):
                 chunks.append(load(open(path, 'rb')))
                 current_chunk = []
                 gc.collect()
-                batch /= 2
+                batch //= 2
                 limit = self._next_limit()
                 MemoryBytesSpilled += (used_memory - get_used_memory()) << 20
                 DiskBytesSpilled += os.path.getsize(path)

python/pyspark/tests.py

@@ -31,10 +31,8 @@
 import time
 import zipfile
 import random
-import itertools
 import threading
 import hashlib
-from StringIO import StringIO
 
 from py4j.protocol import Py4JJavaError
 
@@ -50,6 +48,11 @@
         xrange = range
         basestring = str
 
+if sys.version >= "3":
+    from io import StringIO
+else:
+    from StringIO import StringIO
+
 
 from pyspark.conf import SparkConf
 from pyspark.context import SparkContext