make sure node.children are always sorted

even after calling shift_* methods

Author: martinpopel

udapi/core/node.py

@@ -590,6 +590,7 @@ def _shift_before_ord(self, reference_ord, without_children=False):
                     all_nodes[i_ord - 1]._ord = i_ord
                 all_nodes[reference_ord - 1] = self
                 self._ord = reference_ord
+            self._parent._children.sort()
             return
 
         nodes_to_move = self.descendants(add_self=True)
@@ -615,6 +616,7 @@ def _shift_before_ord(self, reference_ord, without_children=False):
             for node in nodes_to_move:
                 all_nodes[trg_ord - 1], node._ord = node, trg_ord
                 trg_ord += 1
+            self._parent._children.sort()
             return
 
         # First, move a node from position src_ord to position trg_ord RIGHT-ward.
@@ -648,6 +650,7 @@ def _shift_before_ord(self, reference_ord, without_children=False):
         for node in nodes_to_move:
             all_nodes[trg_ord - 1], node._ord = node, trg_ord
             trg_ord += 1
+        self._parent._children.sort()
 
     def shift_after_node(self, reference_node, without_children=False, skip_if_descendant=False):
         """Shift this node after the reference_node."""

udapi/core/tests/test_node.py

@@ -61,6 +61,9 @@ def test_topology(self):
         nodes[0].shift_after_node(nodes[1])
         self.assertEqual([node.ord for node in nodes], [2, 1, 3, 4, 5, 6])
         self.assertEqual([node.ord for node in root.descendants()], [1, 2, 3, 4, 5, 6])
+        self.assertEqual([node.ord for node in nodes[1].children], [2, 3, 4])
+        nodes[3].shift_before_node(nodes[2])
+        self.assertEqual([node.ord for node in nodes[1].children], [2, 3, 6])
 
     def test_draw(self):
         """Test the draw() method, which uses udapi.block.write.textmodetrees."""