Disconnect from Bluetooth devices before the server stops

The polling threads are daemon threads, so a stop ended the server in the middle of a Bluetooth read. The read got no disconnect, and the adapter kept an open connection or a scan in progress.

The server now sets the stop event at exit, closes its socket, and waits at most 20 seconds for the polling threads. A Bluetooth read that sees the stop event cancels its current step, disconnects, and returns. A read that waits for the adapter does not connect after a stop.

tests/test_ecoflow_bt.py

@@ -9,6 +9,8 @@ import asyncio
 import importlib.util
 import struct
 import sys
+import threading
+import time
 from argparse import Namespace
 from dataclasses import asdict
 from itertools import permutations
@@ -538,6 +540,78 @@ def test_successful_collection_logs_no_failure(monkeypatch, capsys):
     assert capsys.readouterr().out == ""
 
 
+def _stoppable_device(monkeypatch, **steps):
+    """Stand-in device that records whether its disconnect ran in full."""
+    events = []
+
+    async def disconnect():
+        events.append("disconnect started")
+        await asyncio.sleep(0.05)
+        events.append("disconnect done")
+
+    fake = Mock(
+        connect=AsyncMock(return_value=True), wait_authenticated=AsyncMock(return_value=True),
+        wait_for_measurements=AsyncMock(return_value=set()), disconnect=disconnect,
+        _pkt_count=1, last_error=None,
+    )
+    fake.configure_mock(**steps)
+    monkeypatch.setattr("bmspy.ecoflow_bt.EcoFlowBTDevice", Mock(return_value=fake))
+    monkeypatch.setattr("bmspy.ecoflow_bt._STOP_POLL_SECONDS", 0.01)
+    monkeypatch.setattr("bmspy.ecoflow_bt._last_missing", {})
+    return fake, events
+
+
+@pytest.mark.parametrize("step", ["connect", "wait_authenticated", "wait_for_measurements"])
+def test_stop_during_a_collection_disconnects_before_it_returns(monkeypatch, capsys, step):
+    """A server that stops in the middle of a read must not leave the link open."""
+    stop = threading.Event()
+
+    async def interrupted(*args, **kwargs):
+        stop.set()
+        await asyncio.sleep(30)
+
+    fake, events = _stoppable_device(monkeypatch, **{step: interrupted})
+    config = initialise_device(ADDRESS, SERIAL, "test-user", listen_duration=0)
+    started = time.monotonic()
+    assert collect_data(config, stop=stop) is False
+    assert time.monotonic() - started < 5
+    assert events == ["disconnect started", "disconnect done"]
+    lines = capsys.readouterr().out.splitlines()
+    assert len(lines) == 1
+    assert lines[0].endswith(f"ecoflow_bt [{ADDRESS}]: read stopped, device disconnected")
+
+
+def test_stop_during_the_disconnect_lets_the_disconnect_finish(monkeypatch):
+    stop = threading.Event()
+    fake, events = _stoppable_device(monkeypatch)
+    slow_disconnect = fake.disconnect
+
+    async def disconnect():
+        stop.set()
+        await slow_disconnect()
+
+    fake.disconnect = disconnect
+    config = initialise_device(ADDRESS, SERIAL, "test-user", listen_duration=0)
+    assert collect_data(config, stop=stop) is fake.snapshot
+    assert events == ["disconnect started", "disconnect done"]
+
+
+def test_collection_does_not_connect_after_stop(monkeypatch):
+    stop = threading.Event()
+    stop.set()
+    device = Mock()
+    monkeypatch.setattr("bmspy.ecoflow_bt.EcoFlowBTDevice", device)
+    assert collect_data(initialise_device(ADDRESS, SERIAL, "test-user"), stop=stop) is False
+    device.assert_not_called()
+
+
+def test_collection_with_an_unset_stop_event_returns_the_snapshot(monkeypatch):
+    fake, events = _stoppable_device(monkeypatch)
+    config = initialise_device(ADDRESS, SERIAL, "test-user", listen_duration=0)
+    assert collect_data(config, stop=threading.Event()) is fake.snapshot
+    assert events == ["disconnect started", "disconnect done"]
+
+
 def test_connect_records_the_reason_for_a_failure(monkeypatch):
     client = Mock(connect=AsyncMock(side_effect=TimeoutError("no answer")), disconnect=AsyncMock(), is_connected=False)
     monkeypatch.setitem(sys.modules, "bleak", SimpleNamespace(BleakClient=Mock(return_value=client)))