curds: Add a node.has_sibling() function

The UI can use this to determine if this is the first node added to the
parent.

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

curds/playlist/node.py

@@ -51,6 +51,9 @@ class PlaylistNode:
             return [ ]
         return self.parent.get_path() + [ self.node_index() ]
 
+    def has_sibling(self):
+        return (self.next_child != None) or (self.prev_child != None)
+
     def lookup(self, name):
         name = self.__normalize__(name)
         for node in self.children:

curds/playlist/test_node.py

@@ -159,6 +159,18 @@ class TestPlaylistNode(unittest.TestCase):
         self.assertEqual(a.parent, root)
         self.assertIsNone(root.parent)
 
+    def test_node_has_sibling(self):
+        root = node.PlaylistNode()
+        a = node.PlaylistNode("a")
+        b = node.PlaylistNode("b")
+
+        root.append_child(a)
+        root.append_child(b)
+
+        self.assertFalse(root.has_sibling())
+        self.assertTrue( a.has_sibling())
+        self.assertTrue( b.has_sibling())
+
     def test_node_get_path(self):
         root = node.PlaylistNode()
         a = node.PlaylistNode("a")