Added multidb support

No change required to upgrade to multiple databases. Aliases are used
to describe the database and these can be manually registered or fall
through to a default alias using connect.

Made get_connection and get_db first class members of the connection class.
Old style _get_connection and _get_db still supported.

Refs: #84 #87 #93 #215

tests/connection.py

@@ -0,0 +1,48 @@
+import unittest
+import pymongo
+
+import mongoengine.connection
+
+from mongoengine import *
+from mongoengine.connection import get_db, get_connection
+
+
+class ConnectionTest(unittest.TestCase):
+
+    def tearDown(self):
+        mongoengine.connection._connection_settings = {}
+        mongoengine.connection._connections = {}
+        mongoengine.connection._dbs = {}
+
+    def test_connect(self):
+        """Ensure that the connect() method works properly.
+        """
+        connect('mongoenginetest')
+
+        conn = get_connection()
+        self.assertTrue(isinstance(conn, pymongo.connection.Connection))
+
+        db = get_db()
+        self.assertTrue(isinstance(db, pymongo.database.Database))
+        self.assertEqual(db.name, 'mongoenginetest')
+
+        connect('mongoenginetest2', alias='testdb')
+        conn = get_connection('testdb')
+        self.assertTrue(isinstance(conn, pymongo.connection.Connection))
+
+    def test_register_connection(self):
+        """Ensure that connections with different aliases may be registered.
+        """
+        register_connection('testdb', 'mongoenginetest2')
+
+        self.assertRaises(ConnectionError, get_connection)
+        conn = get_connection('testdb')
+        self.assertTrue(isinstance(conn, pymongo.connection.Connection))
+
+        db = get_db('testdb')
+        self.assertTrue(isinstance(db, pymongo.database.Database))
+        self.assertEqual(db.name, 'mongoenginetest2')
+
+
+if __name__ == '__main__':
+    unittest.main()

tests/dereference.py

@@ -1,7 +1,7 @@
 import unittest
 
 from mongoengine import *
-from mongoengine.connection import _get_db
+from mongoengine.connection import get_db
 from mongoengine.tests import query_counter
 
 
@@ -9,7 +9,7 @@ class FieldTest(unittest.TestCase):
 
     def setUp(self):
         connect(db='mongoenginetest')
-        self.db = _get_db()
+        self.db = get_db()
 
     def test_list_item_dereference(self):
         """Ensure that DBRef items in ListFields are dereferenced.

tests/document.py

@@ -5,22 +5,18 @@ import warnings
 
 from datetime import datetime
 
-import pymongo
-import pickle
-import weakref
-
 from fixtures import Base, Mixin, PickleEmbedded, PickleTest
 
 from mongoengine import *
-from mongoengine.base import _document_registry, NotRegistered, InvalidDocumentError
-from mongoengine.connection import _get_db
+from mongoengine.base import NotRegistered, InvalidDocumentError
+from mongoengine.connection import get_db
 
 
 class DocumentTest(unittest.TestCase):
 
     def setUp(self):
         connect(db='mongoenginetest')
-        self.db = _get_db()
+        self.db = get_db()
 
         class Person(Document):
             name = StringField()

tests/dynamic_document.py

@@ -1,13 +1,14 @@
 import unittest
 
 from mongoengine import *
-from mongoengine.connection import _get_db
+from mongoengine.connection import get_db
+
 
 class DynamicDocTest(unittest.TestCase):
 
     def setUp(self):
         connect(db='mongoenginetest')
-        self.db = _get_db()
+        self.db = get_db()
 
         class Person(DynamicDocument):
             name = StringField()

tests/fields.py

@@ -6,7 +6,7 @@ import uuid
 from decimal import Decimal
 
 from mongoengine import *
-from mongoengine.connection import _get_db
+from mongoengine.connection import get_db
 from mongoengine.base import _document_registry, NotRegistered
 
 TEST_IMAGE_PATH = os.path.join(os.path.dirname(__file__), 'mongoengine.png')
@@ -16,7 +16,7 @@ class FieldTest(unittest.TestCase):
 
     def setUp(self):
         connect(db='mongoenginetest')
-        self.db = _get_db()
+        self.db = get_db()
 
     def test_default_values(self):
         """Ensure that default field values are used when creating a document.

tests/fixtures.py

@@ -1,9 +1,6 @@
 from datetime import datetime
-import pymongo
 
 from mongoengine import *
-from mongoengine.base import BaseField
-from mongoengine.connection import _get_db
 
 
 class PickleEmbedded(EmbeddedDocument):

tests/queryset.py

@@ -7,7 +7,7 @@ from mongoengine.queryset import (QuerySet, QuerySetManager,
                                   MultipleObjectsReturned, DoesNotExist,
                                   QueryFieldList)
 from mongoengine import *
-from mongoengine.connection import _get_connection
+from mongoengine.connection import get_connection
 from mongoengine.tests import query_counter
 
 
@@ -2276,7 +2276,7 @@ class QuerySetTest(unittest.TestCase):
 
         # check that polygon works for users who have a server >= 1.9
         server_version = tuple(
-            _get_connection().server_info()['version'].split('.')
+            get_connection().server_info()['version'].split('.')
         )
         required_version = tuple("1.9.0".split("."))
         if server_version >= required_version: