From 6f943da688bc0fe7b91311d59c3434e5675fea4b Mon Sep 17 00:00:00 2001
From: Alex Morson <alexmorson@btinternet.com>
Date: Tue, 19 May 2026 21:47:52 +0100
Subject: [PATCH] Support nested batching of broadcasts

This isn't currently used, but I can easily see myself refactoring stuff
in a way that causes this to happen, so it would be nice if it worked.
---
 src/dusted/broadcaster.py |  5 +++--
 tests/test_broadcaster.py | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 2 deletions(-)
 create mode 100644 tests/test_broadcaster.py

diff --git a/src/dusted/broadcaster.py b/src/dusted/broadcaster.py
index 0e51ab0..12a1c43 100644
--- a/src/dusted/broadcaster.py
+++ b/src/dusted/broadcaster.py
@@ -14,11 +14,12 @@ def __init__(self) -> None:
     @contextmanager
     def batch(self) -> Generator[None, None, None]:
         """Batch any events until the context manager has closed."""
+        was_batching = self._batching
+        self._batching = True
         try:
-            self._batching = True
             yield
         finally:
-            self._batching = False
+            self._batching = was_batching
             if self._broadcast_scheduled:
                 self.broadcast()
 
diff --git a/tests/test_broadcaster.py b/tests/test_broadcaster.py
new file mode 100644
index 0000000..7fdd22e
--- /dev/null
+++ b/tests/test_broadcaster.py
@@ -0,0 +1,36 @@
+from unittest import TestCase
+from unittest.mock import Mock
+
+from dusted.broadcaster import Broadcaster
+
+
+class TestBroadcaster(TestCase):
+    def test_multiple_subscribers(self):
+        """Test that multiple subscribers get notified."""
+
+        broadcaster = Broadcaster()
+        mock_callback_1 = Mock(spec_set=[])
+        mock_callback_2 = Mock(spec_set=[])
+        broadcaster.subscribe(mock_callback_1)
+        broadcaster.subscribe(mock_callback_2)
+
+        broadcaster.broadcast()
+
+        mock_callback_1.assert_called_once()
+        mock_callback_2.assert_called_once()
+
+    def test_nested_batch(self):
+        """Test that nested batching works."""
+
+        broadcaster = Broadcaster()
+        mock_callback = Mock(spec_set=[])
+        broadcaster.subscribe(mock_callback)
+
+        with broadcaster.batch():
+            with broadcaster.batch():
+                broadcaster.broadcast()
+            broadcaster.broadcast()
+
+            mock_callback.assert_not_called()
+
+        mock_callback.assert_called_once()