Merge pull request #2536 from davep/expand-tree-expand-messages

Ensure that `TreeNode` messages are posted when via-API changes are made

CHANGELOG.md

@@ -15,6 +15,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Fixed
 
 - Fixed `ZeroDivisionError` in `resolve_fraction_unit` https://github.com/Textualize/textual/issues/2502
+- Fixed `TreeNode.expand` and `TreeNode.expand_all` not posting a `Tree.NodeExpanded` message https://github.com/Textualize/textual/issues/2535
+- Fixed `TreeNode.collapse` and `TreeNode.collapse_all` not posting a `Tree.NodeCollapsed` message https://github.com/Textualize/textual/issues/2535
+- Fixed `TreeNode.toggle` and `TreeNode.toggle_all` not posting a `Tree.NodeExpanded` or `Tree.NodeCollapsed` message https://github.com/Textualize/textual/issues/2535
 
 ## [0.24.1] - 2023-05-08
 

src/textual/widgets/_tree.py

@@ -207,6 +207,7 @@ class TreeNode(Generic[TreeDataType]):
         """
         self._expanded = True
         self._updates += 1
+        self._tree.post_message(Tree.NodeExpanded(self._tree, self))
         if expand_all:
             for child in self.children:
                 child._expand(expand_all)
@@ -239,6 +240,7 @@ class TreeNode(Generic[TreeDataType]):
         """
         self._expanded = False
         self._updates += 1
+        self._tree.post_message(Tree.NodeCollapsed(self._tree, self))
         if collapse_all:
             for child in self.children:
                 child._collapse(collapse_all)
@@ -1157,10 +1159,8 @@ class Tree(Generic[TreeDataType], ScrollView, can_focus=True):
             return
         if node.is_expanded:
             node.collapse()
-            self.post_message(self.NodeCollapsed(self, node))
         else:
             node.expand()
-            self.post_message(self.NodeExpanded(self, node))
 
     async def _on_click(self, event: events.Click) -> None:
         meta = event.style.meta

tests/tree/test_tree_messages.py

@@ -78,6 +78,20 @@ async def test_tree_node_expanded_message() -> None:
         assert pilot.app.messages == [("NodeExpanded", "test-tree")]
 
 
+async def tree_node_expanded_by_code_message() -> None:
+    """Expanding a node via the API should result in an expanded message being posted."""
+    async with TreeApp().run_test() as pilot:
+        pilot.app.query_one(Tree).root.children[0].expand()
+        assert pilot.app.messages == [("NodeExpanded", "test-tree")]
+
+
+async def tree_node_all_expanded_by_code_message() -> None:
+    """Expanding all nodes via the API should result in expanded messages being posted."""
+    async with TreeApp().run_test() as pilot:
+        pilot.app.query_one(Tree).root.children[0].expand_all()
+        assert pilot.app.messages == [("NodeExpanded", "test-tree")]
+
+
 async def test_tree_node_collapsed_message() -> None:
     """Collapsing a node should result in a collapsed message being emitted."""
     async with TreeApp().run_test() as pilot:
@@ -89,6 +103,46 @@ async def test_tree_node_collapsed_message() -> None:
         ]
 
 
+async def tree_node_collapsed_by_code_message() -> None:
+    """Collapsing a node via the API should result in a collapsed message being posted."""
+    async with TreeApp().run_test() as pilot:
+        pilot.app.query_one(Tree).root.children[0].expand().collapse()
+        assert pilot.app.messages == [
+            ("NodeExpanded", "test-tree"),
+            ("NodeCollapsed", "test-tree"),
+        ]
+
+
+async def tree_node_all_collapsed_by_code_message() -> None:
+    """Collapsing all nodes via the API should result in collapsed messages being posted."""
+    async with TreeApp().run_test() as pilot:
+        pilot.app.query_one(Tree).root.children[0].expand_all().collapse_all()
+        assert pilot.app.messages == [
+            ("NodeExpanded", "test-tree"),
+            ("NodeCollapsed", "test-tree"),
+        ]
+
+
+async def tree_node_toggled_by_code_message() -> None:
+    """Toggling a node twice via the API should result in expanded and collapsed messages."""
+    async with TreeApp().run_test() as pilot:
+        pilot.app.query_one(Tree).root.children[0].toggle().toggle()
+        assert pilot.app.messages == [
+            ("NodeExpanded", "test-tree"),
+            ("NodeCollapsed", "test-tree"),
+        ]
+
+
+async def tree_node_all_toggled_by_code_message() -> None:
+    """Toggling all nodes twice via the API should result in expanded and collapsed messages."""
+    async with TreeApp().run_test() as pilot:
+        pilot.app.query_one(Tree).root.children[0].toggle_all().toggle_all()
+        assert pilot.app.messages == [
+            ("NodeExpanded", "test-tree"),
+            ("NodeCollapsed", "test-tree"),
+        ]
+
+
 async def test_tree_node_highlighted_message() -> None:
     """Highlighting a node should result in a highlighted message being emitted."""
     async with TreeApp().run_test() as pilot: