test: stop Flagsmith background threads via an autouse fixture

Flagsmith(...) can start polling, streaming and event-processor background
threads. Track every instance created during a test and stop its threads
on teardown so they don't leak across the suite — previously a leaked
polling thread could call a class-level-patched update_environment in a
later test. Replaces the scattered per-test try/finally cleanup.

Author: gagantrivedi

tests/conftest.py

@@ -23,6 +23,32 @@
 DATA_DIR = os.path.join(os.path.dirname(__file__), "data")
 
 
+@pytest.fixture(autouse=True)
+def stop_flagsmith_background_threads(
+    monkeypatch: pytest.MonkeyPatch,
+) -> Generator[None, None, None]:
+    # Flagsmith starts polling, streaming and event-processor background
+    # threads. Track every instance created during a test and stop its threads
+    # on teardown so they don't leak across the suite (mirroring __del__, but
+    # deterministically rather than at GC).
+    instances: typing.List[Flagsmith] = []
+    original_init = Flagsmith.__init__
+
+    def tracking_init(self: Flagsmith, *args: typing.Any, **kwargs: typing.Any) -> None:
+        instances.append(self)
+        original_init(self, *args, **kwargs)
+
+    monkeypatch.setattr(Flagsmith, "__init__", tracking_init)
+    yield
+    for flagsmith in instances:
+        if getattr(flagsmith, "environment_data_polling_manager_thread", None):
+            flagsmith.environment_data_polling_manager_thread.stop()
+        if getattr(flagsmith, "event_stream_thread", None):
+            flagsmith.event_stream_thread.stop()
+        if flagsmith._event_processor:
+            flagsmith._event_processor.stop()
+
+
 @pytest.fixture()
 def analytics_processor() -> AnalyticsProcessor:
     return AnalyticsProcessor(

tests/test_flagsmith.py

@@ -959,12 +959,8 @@ def test_track_event_raises_without_config(api_key: str) -> None:
 
 def test_track_event_rejects_reserved_prefix(api_key: str) -> None:
     flagsmith = Flagsmith(environment_key=api_key, enable_events=True)
-    try:
-        with pytest.raises(ValueError, match='reserved "\\$" prefix'):
-            flagsmith.track_event("$made_up")
-    finally:
-        if flagsmith._event_processor:
-            flagsmith._event_processor.stop()
+    with pytest.raises(ValueError, match='reserved "\\$" prefix'):
+        flagsmith.track_event("$made_up")
 
 
 def test_event_processor_config_without_enable_events_raises(api_key: str) -> None:
@@ -978,15 +974,11 @@ def test_event_processor_config_without_enable_events_raises(api_key: str) -> No
 
 def test_enable_events_without_config_uses_default(api_key: str) -> None:
     flagsmith = Flagsmith(environment_key=api_key, enable_events=True)
-    try:
-        assert flagsmith._event_processor is not None
-        assert (
-            flagsmith._event_processor._batch_endpoint
-            == "https://events.api.flagsmith.com/v1/events"
-        )
-    finally:
-        if flagsmith._event_processor:
-            flagsmith._event_processor.stop()
+    assert flagsmith._event_processor is not None
+    assert (
+        flagsmith._event_processor._batch_endpoint
+        == "https://events.api.flagsmith.com/v1/events"
+    )
 
 
 def test_track_event_delegates_to_event_processor(