provide a virtual / dummy folder root object for top-down folder creation and access

scopes/storage/folder.py

@@ -22,15 +22,26 @@ class Folder(Track):
     def __getitem__(self, key):
         value = self.container.queryLast(parent=self.uid, name=key)
         if value is None:
-            raise KeyError
+            raise KeyError(key)
         return value
 
     def __setitem__(self, key, value):
-        value.head['parent'] = self.uid
+        value.set('parent', self.uid)
-        value.head['name']= key
+        value.set('name', key)
         self.container.save(value)
 
 
+class Root(Folder):
+    """A dummy (virtual) root folder for creating real folders
+       using the Folder API."""
+
+    def __init__(self, storage):
+        cont = storage.create(Folders)
+        super(Root, self).__init__(container=cont)
+
+    uid = ''
+
+
 @registerContainerClass
 class Folders(Container):
 

scopes/storage/tracking.py

@@ -36,6 +36,15 @@ class Track(object):
         self.trackId = trackId
         self.container = container
 
+    def set(self, attr, value):
+        if attr in self.headFields:
+            if value is None:
+                value = ''
+            self.head[attr] = value
+            setattr(self, attr, value)
+        else:
+            raise AttributeError(attr)
+
     def update(self, data, overwrite=False):
         if data is None:
             return

tests/test_storage.py

@@ -72,18 +72,16 @@ class Test(unittest.TestCase):
 
     def testFolder(self):
         storage.dropTable('folders')
-        cont = storage.create(folder.Folders)
+        root = folder.Root(storage)
-        self.assertEqual(list(cont.query(parent='')), [])
+        self.assertEqual(list(root.keys()), [])
-        cont.save(folder.Folder('', 'root'))
+        root['top'] = folder.Folder()
-        folders = list(cont.query(parent=''))
+        self.assertEqual(list(root.keys()), ['top'])
-        self.assertEqual(len(folders), 1)
+        top = root['top']
-        root = folders[0]
+        top['child1'] = folder.Folder(data=dict(title='First Child'))
-        root['child1'] = folder.Folder(data=dict(title='First Child'))
+        self.assertEqual(list(top.keys()), ['child1'])
-        folders = list(cont.query(parent=root.uid))
+        ch1 = top['child1']
-        self.assertEqual(len(folders), 1)
+        self.assertEqual(ch1.parent, top.uid)
-        ch1 = root['child1']
+        assert list(top.keys()) == ['child1']
-        self.assertEqual(ch1.parent, root.uid)
-        assert list(root.keys()) == ['child1']
 
 def suite():
     return unittest.TestSuite((