Change behavior in utils.import_object().

Fix bug 972859.

Prior to this patch, utils.import_object(foo) and
utils.import_class(foo) would return the same thing if foo was the path
to a class.  This patch changes utils.import_object() to return an
instance of the class, instead, also allowing you to pass in arguments
to the constructor.

This patch also removes the odd behavior of import_object() to be able
to also import a module.  Instead, a new function import_module() has
been added.

Finally, the three import helpers have been moved to a new module,
importutils.

Change-Id: Ia2ea64c965692f8c3a29adec332dd93a83980070

1 files changed, 49 insertions, 0 deletions

diff --git a/tests/unit/test_importutils.py b/tests/unit/test_importutils.py
new file mode 100644
index 0000000..4cc12ab
--- /dev/null
+++ b/tests/unit/test_importutils.py
@@ -0,0 +1,49 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2011 OpenStack LLC.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import datetime
+import sys
+import unittest
+
+from openstack.common import exception
+from openstack.common import importutils
+
+
+class ImportUtilsTest(unittest.TestCase):
+    # NOTE(jkoelker) There has GOT to be a way to test this. But mocking
+    #                __import__ is the devil. Right now we just make
+    #               sure we can import something from the stdlib
+    def test_import_class(self):
+        dt = importutils.import_class('datetime.datetime')
+        self.assertEqual(sys.modules['datetime'].datetime, dt)
+
+    def test_import_bad_class(self):
+        self.assertRaises(exception.NotFound, importutils.import_class,
+                          'lol.u_mad.brah')
+
+    def test_import_module(self):
+        dt = importutils.import_module('datetime')
+        self.assertEqual(sys.modules['datetime'], dt)
+
+    def test_import_object(self):
+        dt = importutils.import_object('datetime.time')
+        self.assertTrue(isinstance(dt, sys.modules['datetime'].time))
+
+    def test_import_object_with_args(self):
+        dt = importutils.import_object('datetime.datetime', 2012, 4, 5)
+        self.assertTrue(isinstance(dt, sys.modules['datetime'].datetime))
+        self.assertEqual(dt, datetime.datetime(2012, 4, 5))