test for unmount

Author: willmcgugan

src/textual/app.py

@@ -638,11 +638,18 @@ async def _press_keys(self, keys: Iterable[str]) -> None:
         await app._animator.wait_for_idle()
 
     @asynccontextmanager
-    async def run_test(self, *, headless: bool = True):
+    async def run_test(
+        self,
+        *,
+        headless: bool = True,
+        size: tuple[int, int] | None = (80, 24),
+    ):
         """An asynchronous context manager for testing app.
 
         Args:
             headless (bool, optional): Run in headless mode (no output or input). Defaults to True.
+            size (tuple[int, int] | None, optional): Force terminal size to `(WIDTH, HEIGHT)`,
+                or None to auto-detect. Defaults to None.
 
         """
         from .pilot import Pilot
@@ -655,7 +662,11 @@ def on_app_ready() -> None:
             app_ready_event.set()
 
         async def run_app(app) -> None:
-            await app._process_messages(ready_callback=on_app_ready, headless=headless)
+            await app._process_messages(
+                ready_callback=on_app_ready,
+                headless=headless,
+                terminal_size=size,
+            )
 
         # Launch the app in the "background"
         app_task = asyncio.create_task(run_app(app))
@@ -1135,24 +1146,30 @@ async def _process_messages(
 
         async def run_process_messages():
             """The main message loop, invoke below."""
+
+            async def invoke_ready_callback() -> None:
+                if ready_callback is not None:
+                    ready_result = ready_callback()
+                    if inspect.isawaitable(ready_result):
+                        await ready_result
+
             try:
-                await self._dispatch_message(events.Compose(sender=self))
-                await self._dispatch_message(events.Mount(sender=self))
-            finally:
-                self._mounted_event.set()
+                try:
+                    await self._dispatch_message(events.Compose(sender=self))
+                    await self._dispatch_message(events.Mount(sender=self))
+                finally:
+                    self._mounted_event.set()
 
-            Reactive._initialize_object(self)
+                Reactive._initialize_object(self)
 
-            self.stylesheet.update(self)
-            self.refresh()
+                self.stylesheet.update(self)
+                self.refresh()
 
-            await self.animator.start()
-            await self._ready()
+                await self.animator.start()
 
-            if ready_callback is not None:
-                ready_result = ready_callback()
-                if inspect.isawaitable(ready_result):
-                    await ready_result
+            finally:
+                await self._ready()
+                await invoke_ready_callback()
 
             self._running = True
 
@@ -1356,7 +1373,7 @@ async def _shutdown(self) -> None:
         await self._close_all()
         await self._close_messages()
 
-        await self._dispatch_message(events.UnMount(sender=self))
+        await self._dispatch_message(events.Unmount(sender=self))
 
         self._print_error_renderables()
         if self.devtools is not None and self.devtools.is_connected:

src/textual/events.py

@@ -123,7 +123,7 @@ class Mount(Event, bubble=False, verbose=False):
     """Sent when a widget is *mounted* and may receive messages."""
 
 
-class UnMount(Mount, bubble=False, verbose=False):
+class Unmount(Mount, bubble=False, verbose=False):
     """Sent when a widget is unmounted and may not longer receive messages."""
 
 

src/textual/message_pump.py

@@ -283,7 +283,7 @@ async def _close_messages(self) -> None:
         for timer in stop_timers:
             await timer.stop()
         self._timers.clear()
-        await self._message_queue.put(events.UnMount(sender=self))
+        await self._message_queue.put(events.Unmount(sender=self))
         await self._message_queue.put(None)
         if self._task is not None and asyncio.current_task() != self._task:
             # Ensure everything is closed before returning

tests/test_unmount.py

@@ -0,0 +1,50 @@
+from textual.app import App, ComposeResult
+from textual import events
+from textual.containers import Container
+from textual.screen import Screen
+
+
+async def test_unmount():
+    """Text unmount events are received in reverse DOM order."""
+    unmount_ids: list[str] = []
+
+    class UnmountWidget(Container):
+        def on_unmount(self, event: events.Unmount):
+            unmount_ids.append(f"{self.__class__.__name__}#{self.id}")
+
+    class MyScreen(Screen):
+        def compose(self) -> ComposeResult:
+            yield UnmountWidget(
+                UnmountWidget(
+                    UnmountWidget(id="bar1"), UnmountWidget(id="bar2"), id="bar"
+                ),
+                UnmountWidget(
+                    UnmountWidget(id="baz1"), UnmountWidget(id="baz2"), id="baz"
+                ),
+                id="top",
+            )
+
+        def on_unmount(self, event: events.Unmount):
+            unmount_ids.append(f"{self.__class__.__name__}#{self.id}")
+
+    class UnmountApp(App):
+        async def on_mount(self) -> None:
+            self.push_screen(MyScreen(id="main"))
+
+    app = UnmountApp()
+    async with app.run_test() as pilot:
+        await pilot.pause()  # TODO remove when push_screen is awaitable
+        await pilot.exit(None)
+
+    expected = [
+        "UnmountWidget#bar1",
+        "UnmountWidget#bar2",
+        "UnmountWidget#baz1",
+        "UnmountWidget#baz2",
+        "UnmountWidget#bar",
+        "UnmountWidget#baz",
+        "UnmountWidget#top",
+        "MyScreen#main",
+    ]
+
+    assert unmount_ids == expected