curds: Add a way to find a node's path

A path is a list of indices in the tree, which can easily be translated
into a GtkTreePath

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

curds/playlist/node.py

@@ -29,6 +29,11 @@ class PlaylistNode:
         self.__link_children__(prev, child)
         return self.children.index(child)
 
+    def get_path(self):
+        if self.parent == None:
+            return [ ]
+        return self.parent.get_path() + [ self.node_index() ]
+
     def node_index(self):
         if self.parent == None:
             return None

curds/playlist/test_node.py

@@ -124,3 +124,18 @@ class TestPlaylistNode(unittest.TestCase):
         self.assertEqual(b.parent, a)
         self.assertEqual(a.parent, root)
         self.assertIsNone(root.parent)
+
+    def test_node_get_path(self):
+        root = node.PlaylistNode()
+        a = node.PlaylistNode("a")
+        b = node.PlaylistNode("b")
+        c = node.PlaylistNode("c")
+
+        root.append_child(a)
+        a.append_child(b)
+        b.append_child(c)
+
+        self.assertEqual(root.get_path(), [ ])
+        self.assertEqual(a.get_path(),    [ 0 ])
+        self.assertEqual(b.get_path(),    [ 0, 0 ])
+        self.assertEqual(c.get_path(),    [ 0, 0, 0 ])