do not mock private methods of objects from libraries

This patch fixes tests that were using mock to replace a private method
of a library instead of using the public testing interface provided by
that library. The new release of stevedore changes the name of that
private method, which breaks these tests. Because the requirements list
is gated on glance's unit tests, the test failure is preventing other
projects from adopting the new release of stevedore.

Change-Id: Ie9af444e7f8842ffb3e275ede52b802de02e6e99
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

glance/common/glare/loader.py

@@ -43,8 +43,8 @@ CONF.register_opts(plugins_opts)
 
 
 class ArtifactsPluginLoader(object):
-    def __init__(self, namespace):
-        self.mgr = enabled.EnabledExtensionManager(
+    def __init__(self, namespace, test_plugins=None):
+        self.mgr = test_plugins or enabled.EnabledExtensionManager(
             check_func=self._gen_check_func(),
             namespace=namespace,
             propagate_map_exceptions=True,

glance/tests/functional/glare/test_glare.py

@@ -17,9 +17,9 @@ import uuid
 
 import mock
 from oslo_serialization import jsonutils
-import pkg_resources
 import requests
 from six.moves import http_client as http
+from stevedore import extension
 
 from glance.api.glare.v0_1 import glare
 from glance.api.glare.v0_1 import router
@@ -60,20 +60,38 @@ class ArtifactWithBlob(definitions.ArtifactType):
 
 
 def _create_resource():
-    plugins = None
-    mock_this = 'stevedore.extension.ExtensionManager._find_entry_points'
-    with mock.patch(mock_this) as fep:
-        path = 'glance.tests.functional.glare.test_glare'
-        fep.return_value = [
-            pkg_resources.EntryPoint.parse('WithProps=%s:Artifact' % path),
-            pkg_resources.EntryPoint.parse(
-                'NoProp=%s:ArtifactNoProps' % path),
-            pkg_resources.EntryPoint.parse(
-                'NoProp=%s:ArtifactNoProps1' % path),
-            pkg_resources.EntryPoint.parse(
-                'WithBlob=%s:ArtifactWithBlob' % path)
-        ]
-        plugins = loader.ArtifactsPluginLoader('glance.artifacts.types')
+    test_loader = extension.ExtensionManager.make_test_instance(
+        extensions=[
+            extension.Extension(
+                name='WithProps',
+                entry_point=mock.Mock(),
+                plugin=Artifact,
+                obj=None,
+            ),
+            extension.Extension(
+                name='NoProp',
+                entry_point=mock.Mock(),
+                plugin=ArtifactNoProps,
+                obj=None,
+            ),
+            extension.Extension(
+                name='NoProp',
+                entry_point=mock.Mock(),
+                plugin=ArtifactNoProps1,
+                obj=None,
+            ),
+            extension.Extension(
+                name='WithBlob',
+                entry_point=mock.Mock(),
+                plugin=ArtifactWithBlob,
+                obj=None,
+            ),
+        ],
+    )
+    plugins = loader.ArtifactsPluginLoader(
+        'glance.artifacts.types',
+        test_plugins=test_loader,
+    )
     deserializer = glare.RequestDeserializer(plugins=plugins)
     serializer = glare.ResponseSerializer()
     controller = glare.ArtifactsController(plugins=plugins)