Add a keys() method to SQLAlchemy ModelBase

With this additional method, it now possible to write directly
dict(obj), instead of dict(obj.iteritems()), to cast an object to a
dictionary.

Modify also ModelIterator: it doesn't inherit from ModelBase anymore.

Change-Id: I702be362a58155a28482e733e60539d36c039509

2 files changed, 28 insertions, 3 deletions

diff --git a/oslo_db/sqlalchemy/models.py b/oslo_db/sqlalchemy/models.py
index 80fa01d..8edfe72 100644
--- a/oslo_db/sqlalchemy/models.py
+++ b/oslo_db/sqlalchemy/models.py
@@ -90,14 +90,18 @@ class ModelBase(six.Iterator):
 
         Includes attributes from joins.
         """
-        local = dict(self)
+        local = dict((key, value) for key, value in self)
         joined = dict([(k, v) for k, v in six.iteritems(self.__dict__)
                       if not k[0] == '_'])
         local.update(joined)
         return six.iteritems(local)
 
+    def keys(self):
+        """Make the model object behave like a dict."""
+        return [key for key, value in self.iteritems()]
+
 
-class ModelIterator(ModelBase, six.Iterator):
+class ModelIterator(six.Iterator):
 
     def __init__(self, model, columns):
         self.model = model
diff --git a/oslo_db/tests/sqlalchemy/test_models.py b/oslo_db/tests/sqlalchemy/test_models.py
index 4a45576..eac66f5 100644
--- a/oslo_db/tests/sqlalchemy/test_models.py
+++ b/oslo_db/tests/sqlalchemy/test_models.py
@@ -40,7 +40,8 @@ class ModelBaseTest(test_base.DbTestCase):
                         'get',
                         'update',
                         'save',
-                        'iteritems')
+                        'iteritems',
+                        'keys')
         for method in dict_methods:
             self.assertTrue(hasattr(models.ModelBase, method),
                             "Method %s() is not found" % method)
@@ -80,6 +81,18 @@ class ModelBaseTest(test_base.DbTestCase):
         self.ekm.update(h)
         self.assertEqual(dict(self.ekm.iteritems()), expected)
 
+    def test_modelbase_dict(self):
+        h = {'a': '1', 'b': '2'}
+        expected = {
+            'id': None,
+            'smth': None,
+            'name': 'NAME',
+            'a': '1',
+            'b': '2',
+        }
+        self.ekm.update(h)
+        self.assertEqual(dict(self.ekm), expected)
+
     def test_modelbase_iter(self):
         expected = {
             'id': None,
@@ -97,6 +110,14 @@ class ModelBaseTest(test_base.DbTestCase):
 
         self.assertEqual(len(expected), found_items)
 
+    def test_modelbase_keys(self):
+        self.assertEqual(set(self.ekm.keys()),
+                         set(('id', 'smth', 'name')))
+
+        self.ekm.update({'a': '1', 'b': '2'})
+        self.assertEqual(set(self.ekm.keys()),
+                         set(('a', 'b', 'id', 'smth', 'name')))
+
     def test_modelbase_several_iters(self):
         mb = ExtraKeysModel()
         it1 = iter(mb)