Fix incorrect test for list_users

The current test would not fail if incorrect data was returned by
the driver.  The list_roles test also has the same issue.

Fixes bug 1222574

Change-Id: Icc5e76e9453436ac208c5f262d0dd4082b700d02

keystone/tests/test_backend.py

@@ -1739,8 +1739,10 @@ def test_update_user_invalid_name_fails(self):
 
     def test_list_users(self):
         users = self.identity_api.list_users()
-        for test_user in default_fixtures.USERS:
-            self.assertTrue(x for x in users if x['id'] == test_user['id'])
+        self.assertEqual(len(default_fixtures.USERS), len(users))
+        user_ids = set(user['id'] for user in users)
+        expected_user_ids = set(user['id'] for user in default_fixtures.USERS)
+        self.assertEqual(expected_user_ids, user_ids)
 
     def test_list_groups(self):
         group1 = {
@@ -1810,8 +1812,10 @@ def test_list_projects_for_alternate_domain(self):
 
     def test_list_roles(self):
         roles = self.identity_api.list_roles()
-        for test_role in default_fixtures.ROLES:
-            self.assertTrue(x for x in roles if x['id'] == test_role['id'])
+        self.assertEqual(len(default_fixtures.ROLES), len(roles))
+        role_ids = set(role['id'] for role in roles)
+        expected_role_ids = set(role['id'] for role in default_fixtures.ROLES)
+        self.assertEqual(expected_role_ids, role_ids)
 
     def test_delete_project_with_role_assignments(self):
         tenant = {'id': uuid.uuid4().hex, 'name': uuid.uuid4().hex,