Make identity id mapping handle unicode

Identity id mapping is used to create public ids for local entities,
typically stored in LDAP backends. Part of the mapping involves
creating a hash of the local identifiers - but this hashing did
not correctly handle unicode. This patch fixes this.

(cherry picked from commit 4f0107e434)
Closes-Bug: 1419187

Change-Id: Icc2a6bc4a7e88004bbe6f86d3a96cff07be4c6f9

keystone/identity/id_generators/sha256.py

@@ -24,5 +24,5 @@ class Generator(generator.IDGenerator):
     def generate_public_ID(self, mapping):
         m = hashlib.sha256()
         for key in sorted(six.iterkeys(mapping)):
-            m.update(mapping[key])
+            m.update(mapping[key].encode('utf-8'))
         return m.hexdigest()

keystone/tests/test_backend_id_mapping_sql.py

@@ -120,6 +120,7 @@ class SqlIDMapping(test_backend_sql.SqlTests):
                         matchers.HasLength(initial_mappings))
 
     def test_id_mapping_handles_unicode(self):
+        initial_mappings = len(mapping_sql.list_id_mappings())
         local_id = u'fäké1'
         local_entity = {'domain_id': self.domainA['id'],
                         'local_id': local_id,
@@ -128,11 +129,12 @@ class SqlIDMapping(test_backend_sql.SqlTests):
         # Check no mappings for the new local entity
         self.assertIsNone(self.id_mapping_api.get_public_id(local_entity))
 
-        # The mapping generator should handle unicode, although currently this
-        # fails due to bug #1419187
-        self.assertRaises(UnicodeEncodeError,
-                          self.id_mapping_api.create_id_mapping,
-                          local_entity)
+        # Create the new mapping and then read it back
+        public_id = self.id_mapping_api.create_id_mapping(local_entity)
+        self.assertThat(mapping_sql.list_id_mappings(),
+                        matchers.HasLength(initial_mappings + 1))
+        self.assertEqual(
+            public_id, self.id_mapping_api.get_public_id(local_entity))
 
     def test_delete_public_id_is_silent(self):
         # Test that deleting an invalid public key is silent