curds: Add a function for finding the root node of the PlaylistNode tree

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

curds/playlist/node.py

@@ -52,6 +52,11 @@ class PlaylistNode:
             return [ ]
         return self.parent.get_path() + [ self.node_index() ]
 
+    def get_root(self):
+        if self.parent == None:
+            return self
+        return self.parent.get_root()
+
     def has_sibling(self):
         return (self.next_child != None) or (self.prev_child != None)
 

curds/playlist/test_node.py

@@ -211,6 +211,21 @@ class TestPlaylistNode(unittest.TestCase):
         self.assertIsNone(root.get_node([ 0, 1, 0 ]))
         self.assertIsNone(root.get_node([ 1, 0, 0 ]))
 
+    def test_node_get_root(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_root(), root)
+        self.assertEqual(a.get_root(),    root)
+        self.assertEqual(b.get_root(),    root)
+        self.assertEqual(c.get_root(),    root)
+
     def test_node_reset(self):
         root = node.PlaylistNode()
         a = node.PlaylistNode("a")