[PySpark] [SPARK-2954] [SPARK-2948] [SPARK-2910] [SPARK-2101] Python 2.6 Fixes

- Modify python/run-tests to test with Python 2.6
- Use unittest2 when running on Python 2.6.
- Fix issue with namedtuple.
- Skip TestOutputFormat.test_newhadoop on Python 2.6 until SPARK-2951 is fixed.
- Fix MLlib _deserialize_double on Python 2.6.

Closes #1868.  Closes #1042.

Author: Josh Rosen <joshrosen@apache.org>

Closes #1874 from JoshRosen/python2.6 and squashes the following commits:

983d259 [Josh Rosen] [SPARK-2954] Fix MLlib _deserialize_double on Python 2.6.
5d18fd7 [Josh Rosen] [SPARK-2948] [SPARK-2910] [SPARK-2101] Python 2.6 fixes

1 files changed, 10 insertions, 3 deletions

diff --git a/python/pyspark/tests.py b/python/pyspark/tests.py
index 88a61176e5..22b51110ed 100644
--- a/python/pyspark/tests.py
+++ b/python/pyspark/tests.py
@@ -29,9 +29,14 @@ import subprocess
 import sys
 import tempfile
 import time
-import unittest
 import zipfile
 
+if sys.version_info[:2] <= (2, 6):
+    import unittest2 as unittest
+else:
+    import unittest
+
+
 from pyspark.context import SparkContext
 from pyspark.files import SparkFiles
 from pyspark.serializers import read_int
@@ -605,6 +610,7 @@ class TestOutputFormat(PySparkTestCase):
             conf=input_conf).collect())
         self.assertEqual(old_dataset, dict_data)
 
+    @unittest.skipIf(sys.version_info[:2] <= (2, 6), "Skipped on 2.6 until SPARK-2951 is fixed")
     def test_newhadoop(self):
         basepath = self.tempdir.name
         # use custom ArrayWritable types and converters to handle arrays
@@ -905,8 +911,9 @@ class TestSparkSubmit(unittest.TestCase):
         pattern = re.compile(r'^ *\|', re.MULTILINE)
         content = re.sub(pattern, '', content.strip())
         path = os.path.join(self.programDir, name + ".zip")
-        with zipfile.ZipFile(path, 'w') as zip:
-            zip.writestr(name, content)
+        zip = zipfile.ZipFile(path, 'w')
+        zip.writestr(name, content)
+        zip.close()
         return path
 
     def test_single_script(self):