Adding description for testcases - identity part5

When Tempest is used in customer site, often we are required to
provide a testcase list including testcase names and descriptions.
Now no this kind of doc is available, so we can add descriptions
with the format of doc string for every testcase, so later we
can generata such a testcase description list.

There are hundreds of testcases missing descriptions, so we can
add them gradually, and limit the modified files in one patch
for the convenience of reviewing.

Change-Id: I47fc64ac84b4d0ea3da0a9469efec7bd6e0b0f3d
partially-implements: blueprint testcase-description
diff --git a/tempest/api/identity/admin/v3/test_tokens.py b/tempest/api/identity/admin/v3/test_tokens.py
index 5f1b58d..f3a7471 100644
--- a/tempest/api/identity/admin/v3/test_tokens.py
+++ b/tempest/api/identity/admin/v3/test_tokens.py
@@ -24,6 +24,7 @@
 
 
 class TokensV3TestJSON(base.BaseIdentityV3AdminTest):
+    """Test tokens"""
 
     credentials = ['primary', 'admin', 'alt']
 
@@ -123,6 +124,7 @@
 
     @decorators.idempotent_id('08ed85ce-2ba8-4864-b442-bcc61f16ae89')
     def test_get_available_project_scopes(self):
+        """Test getting available project scopes"""
         manager_project_id = self.os_primary.credentials.project_id
         admin_user_id = self.os_admin.credentials.user_id
         admin_role_id = self.get_role_by_name(CONF.identity.admin_role)['id']
@@ -152,10 +154,13 @@
 
     @decorators.idempotent_id('ec5ecb05-af64-4c04-ac86-4d9f6f12f185')
     def test_get_available_domain_scopes(self):
-        # Test for verifying that listing domain scopes for a user works if
-        # the user has a domain role or belongs to a group that has a domain
-        # role. For this test, admin client is used to add roles to alt user,
-        # which performs API calls, to avoid 401 Unauthorized errors.
+        """Test getting available domain scopes
+
+        To verify that listing domain scopes for a user works if
+        the user has a domain role or belongs to a group that has a domain
+        role. For this test, admin client is used to add roles to alt user,
+        which performs API calls, to avoid 401 Unauthorized errors.
+        """
         alt_user_id = self.os_alt.credentials.user_id
 
         def _create_user_domain_role_for_alt_user():