Upgrade pymongo usage from deprecated connection to client

LMS-1551

cms/djangoapps/contentstore/tests/test_contentstore.py

@@ -1604,7 +1604,7 @@ class ContentStoreTest(ModuleStoreTestCase):
         data = parse_json(resp)
         self.assertRegexpMatches(
             data['locator'],
-            r"^MITx.999.Robot_Super_Course/branch/draft/block/chapter([0-9]|[a-f]){3}$"
+            r"^MITx.999.Robot_Super_Course/branch/draft/block/chapter([0-9]|[a-f]){3,}$"
         )
 
     def test_capa_module(self):

common/lib/xmodule/xmodule/contentstore/mongo.py

-from pymongo import Connection
+import pymongo
 import gridfs
 from gridfs.errors import NoFile
 
@@ -24,8 +24,14 @@ class MongoContentStore(ContentStore):
         :param collection: ignores but provided for consistency w/ other doc_store_config patterns
         """
         logging.debug('Using MongoDB for static content serving at host={0} db={1}'.format(host, db))
-
-        _db = Connection(host=host, port=port, **kwargs)[db]
+        _db = pymongo.database.Database(
+            pymongo.MongoClient(
+                host=host,
+                port=port,
+                **kwargs
+            ),
+            db
+        )
 
         if user is not None and password is not None:
             _db.authenticate(user, password)

common/lib/xmodule/xmodule/modulestore/mongo/base.py

@@ -274,25 +274,30 @@ class MongoModuleStore(ModuleStoreWriteBase):
             """
             Create & open the connection, authenticate, and provide pointers to the collection
             """
-            self.collection = pymongo.connection.Connection(
-                host=host,
-                port=port,
-                tz_aware=tz_aware,
-                **kwargs
-            )[db][collection]
+            self.database = pymongo.database.Database(
+                pymongo.MongoClient(
+                    host=host,
+                    port=port,
+                    tz_aware=tz_aware,
+                    **kwargs
+                ),
+                db
+            )
+            self.collection = self.database[collection]
 
             if user is not None and password is not None:
-                self.collection.database.authenticate(user, password)
+                self.database.authenticate(user, password)
 
         do_connection(**doc_store_config)
 
         # Force mongo to report errors, at the expense of performance
-        self.collection.safe = True
+        self.collection.write_concern = {'w': 1}
 
         # Force mongo to maintain an index over _id.* that is in the same order
         # that is used when querying by a location
         self.collection.ensure_index(
-            zip(('_id.' + field for field in Location._fields), repeat(1))
+            zip(('_id.' + field for field in Location._fields), repeat(1)),
+            name="location_index"
         )
 
         if default_class is not None:

common/lib/xmodule/xmodule/modulestore/tests/test_mixed_modulestore.py

@@ -69,7 +69,11 @@ class TestMixedModuleStore(object):
         """
         Set up the database for testing
         """
-        cls.connection = pymongo.connection.Connection(HOST, PORT)
+        cls.connection = pymongo.MongoClient(
+            host=HOST,
+            port=PORT,
+            tz_aware=True,
+        )
         cls.connection.drop_database(DB)
         cls.fake_location = Location(['i4x', 'foo', 'bar', 'vertical', 'baz'])
         cls.import_org, cls.import_course, cls.import_run = IMPORT_COURSEID.split('/')

common/lib/xmodule/xmodule/modulestore/tests/test_mongo.py

@@ -20,7 +20,7 @@ from xmodule.modulestore.xml_importer import import_from_xml, perform_xlint
 from xmodule.contentstore.mongo import MongoContentStore
 
 from xmodule.modulestore.tests.test_modulestore import check_path_to_location
-from IPython.testing.nose_assert_methods import assert_in, assert_not_in
+from IPython.testing.nose_assert_methods import assert_in
 from xmodule.exceptions import NotFoundError
 from xmodule.modulestore.exceptions import InsufficientSpecificationError
 
@@ -39,7 +39,11 @@ class TestMongoModuleStore(object):
     '''Tests!'''
     @classmethod
     def setupClass(cls):
-        cls.connection = pymongo.connection.Connection(HOST, PORT)
+        cls.connection = pymongo.MongoClient(
+            host=HOST,
+            port=PORT,
+            tz_aware=True,
+        )
         cls.connection.drop_database(DB)
 
         # NOTE: Creating a single db for all the tests to save time.  This
@@ -50,8 +54,8 @@ class TestMongoModuleStore(object):
 
     @classmethod
     def teardownClass(cls):
-        cls.connection = pymongo.connection.Connection(HOST, PORT)
-        cls.connection.drop_database(DB)
+        if cls.connection:
+            cls.connection.drop_database(DB)
 
     @staticmethod
     def initdb():