add import_object_ns function

To support bp:virt-driver-cleanup, there is a desire to have shorter
driver strings (i.e. libvirt.LibvirtDriver instead of
nova.virt.libvirt.LibvirtDriver). One way to support this is with
a new import_object variant that takes a namespace to load from.

If the code fails to load the driver in the prefered namespace it
will also try loading the full driver path, before throwing an
exception.

Change-Id: Ib97c92f38685ca89f29890f8015fc413acc744f8

1 files changed, 43 insertions, 0 deletions

diff --git a/tests/unit/test_importutils.py b/tests/unit/test_importutils.py
index acdb217..c41f13b 100644
--- a/tests/unit/test_importutils.py
+++ b/tests/unit/test_importutils.py
@@ -58,6 +58,49 @@ class ImportUtilsTest(unittest.TestCase):
                                         first_arg=False)
         self.assertTrue(obj.__class__.__name__, 'FakeDriver2')
 
+    # namespace tests
+    def test_import_object_ns_optional_arg_not_present(self):
+        obj = importutils.import_object_ns('tests.unit', 'fake.FakeDriver')
+        self.assertTrue(obj.__class__.__name__, 'FakeDriver')
+
+    def test_import_object_ns_optional_arg_present(self):
+        obj = importutils.import_object_ns('tests.unit', 'fake.FakeDriver',
+                                        first_arg=False)
+        self.assertTrue(obj.__class__.__name__, 'FakeDriver')
+
+    def test_import_object_ns_required_arg_not_present(self):
+        # arg 1 isn't optional here
+        self.assertRaises(TypeError, importutils.import_object_ns,
+                          'tests.unit', 'fake.FakeDriver2')
+
+    def test_import_object_ns_required_arg_present(self):
+        obj = importutils.import_object_ns('tests.unit', 'fake.FakeDriver2',
+                                        first_arg=False)
+        self.assertTrue(obj.__class__.__name__, 'FakeDriver2')
+
+    # namespace tests
+    def test_import_object_ns_full_optional_arg_not_present(self):
+        obj = importutils.import_object_ns('tests.unit2',
+                                           'tests.unit.fake.FakeDriver')
+        self.assertTrue(obj.__class__.__name__, 'FakeDriver')
+
+    def test_import_object_ns_full_optional_arg_present(self):
+        obj = importutils.import_object_ns('tests.unit2',
+                                           'tests.unit.fake.FakeDriver',
+                                           first_arg=False)
+        self.assertTrue(obj.__class__.__name__, 'FakeDriver')
+
+    def test_import_object_ns_full_required_arg_not_present(self):
+        # arg 1 isn't optional here
+        self.assertRaises(TypeError, importutils.import_object_ns,
+                          'tests.unit2', 'tests.unit.fake.FakeDriver2')
+
+    def test_import_object_ns_full_required_arg_present(self):
+        obj = importutils.import_object_ns('tests.unit2',
+                                           'tests.unit.fake.FakeDriver2',
+                                           first_arg=False)
+        self.assertTrue(obj.__class__.__name__, 'FakeDriver2')
+
     def test_import_object(self):
         dt = importutils.import_object('datetime.time')
         self.assertTrue(isinstance(dt, sys.modules['datetime'].time))