Improved Command class management.

tests/controls/test_treeview.py

@@ -464,20 +464,20 @@ class TestTreeviewBehaviour:
   def test_i_cannot_ensure_path_with_none(self, root_instance):
     """Test that ensure_path raises ValueError when path is None."""
     tree_view = TreeView(root_instance)
-
+    
     with pytest.raises(ValueError, match="Invalid path.*None"):
       tree_view.ensure_path(None)
-
+  
   def test_i_cannot_ensure_path_with_empty_string(self, root_instance):
     """Test that ensure_path raises ValueError for empty strings after stripping."""
     tree_view = TreeView(root_instance)
-
+    
     with pytest.raises(ValueError, match="Invalid path.*empty"):
       tree_view.ensure_path("   ")
-
+    
     with pytest.raises(ValueError, match="Invalid path.*empty"):
       tree_view.ensure_path("")
-
+    
     with pytest.raises(ValueError, match="Invalid path.*empty"):
       tree_view.ensure_path("...")
   
@@ -531,44 +531,57 @@ class TestTreeviewBehaviour:
   def test_i_cannot_ensure_path_with_only_spaces_parts(self, root_instance):
     """Test that ensure_path raises ValueError for path parts with only spaces."""
     tree_view = TreeView(root_instance)
-
+    
     with pytest.raises(ValueError, match="Invalid path"):
       tree_view.ensure_path("folder1.   .folder2")
-
+  
   def test_ensure_path_returns_last_node_id(self, root_instance):
     """Test that ensure_path returns the ID of the last node in the path."""
     tree_view = TreeView(root_instance)
-
+    
     # Create a path and get the returned ID
     returned_id = tree_view.ensure_path("folder1.folder2.folder3")
-
+    
     # Verify the returned ID is not None
     assert returned_id is not None
-
+    
     # Verify the returned ID corresponds to folder3
     assert returned_id in tree_view._state.items
     assert tree_view._state.items[returned_id].label == "folder3"
-
+    
     # Verify we can use this ID to add a child
     leaf = TreeNode(label="file.txt", type="file")
     tree_view.add_node(leaf, parent_id=returned_id)
-
+    
     assert leaf.parent == returned_id
     assert leaf.id in tree_view._state.items[returned_id].children
-
+  
   def test_ensure_path_returns_existing_node_id(self, root_instance):
     """Test that ensure_path returns ID even when path already exists."""
     tree_view = TreeView(root_instance)
-
+    
     # Create initial path
     first_id = tree_view.ensure_path("folder1.folder2")
-
+    
     # Ensure same path again
     second_id = tree_view.ensure_path("folder1.folder2")
-
+    
     # Should return the same ID
     assert first_id == second_id
     assert tree_view._state.items[first_id].label == "folder2"
+  
+  def test_i_can_add_the_same_node_id_twice(self, root_instance):
+    """Test that adding a node with the same ID as an existing node raises ValueError."""
+    tree_view = TreeView(root_instance)
+    
+    node1 = TreeNode(label="Node", type="folder", id="existing_id")
+    tree_view.add_node(node1)
+    
+    node2 = TreeNode(label="Other Node", type="folder", id="existing_id")
+    tree_view.add_node(node2)
+    
+    assert len(tree_view._state.items) == 1, "Node should not have been added to items"
+    assert tree_view._state.items[node1.id] == node2, "Node should not have been replaced"
 
 
 class TestTreeViewRender: