Fix list_opts test to not check all deps

The list_opts entrypoint test failed unnecessarily when the
dependencies in the packages were inconsistent. This test doesn't
need to verify that the dependencies are consistent, only that the
entrypoint is available and provides the expected function.

Change-Id: I0bb0f2b591c402202104af8daf07d56b514cbb2f

oslo_messaging/tests/test_opts.py

@@ -12,7 +12,7 @@
 #    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 pkg_resources
+import stevedore
 import testtools
 
 try:
@@ -47,10 +47,10 @@ class OptsTestCase(test_utils.BaseTestCase):
 
     def test_entry_point(self):
         result = None
-        for ep in pkg_resources.iter_entry_points('oslo.config.opts'):
-            if ep.name == "oslo.messaging":
-                list_fn = ep.load()
-                result = list_fn()
+        for ext in stevedore.ExtensionManager('oslo.config.opts',
+                                              invoke_on_load=True):
+            if ext.name == "oslo.messaging":
+                result = ext.obj
                 break
 
         self.assertIsNotNone(result)