Add coverage to verify subscribe_voice_assistant cancels tasks on unsub (#750)

tests/test_client.py

@@ -1833,7 +1833,7 @@ async def test_subscribe_voice_assistant_failure(
         APIClient, APIConnection, asyncio.Transport, APIPlaintextFrameHelper
     ],
 ) -> None:
-    """Test subscribe_voice_assistant."""
+    """Test subscribe_voice_assistant failure."""
     client, connection, transport, protocol = api_client
     send = patch_send(client)
     starts = []
@@ -1898,6 +1898,63 @@ async def test_subscribe_voice_assistant_failure(
     assert len(send.mock_calls) == 0
 
 
+@pytest.mark.asyncio
+async def test_subscribe_voice_assistant_cancels_long_running_handle_start(
+    api_client: tuple[
+        APIClient, APIConnection, asyncio.Transport, APIPlaintextFrameHelper
+    ],
+) -> None:
+    """Test subscribe_voice_assistant cancels long running tasks on unsub."""
+    client, connection, transport, protocol = api_client
+    send = patch_send(client)
+    starts = []
+    stops = []
+
+    async def handle_start(
+        conversation_id: str, flags: int, audio_settings: VoiceAssistantAudioSettings
+    ) -> int | None:
+        starts.append((conversation_id, flags, audio_settings))
+        await asyncio.sleep(10)
+        # Return None to indicate failure
+        starts.append("never")
+        return None
+
+    async def handle_stop() -> None:
+        stops.append(True)
+
+    unsub = await client.subscribe_voice_assistant(handle_start, handle_stop)
+    send.assert_called_once_with(SubscribeVoiceAssistantRequest(subscribe=True))
+    send.reset_mock()
+    audio_settings = VoiceAssistantAudioSettings(
+        noise_suppression_level=42,
+        auto_gain=42,
+        volume_multiplier=42,
+    )
+    response: message.Message = VoiceAssistantRequest(
+        conversation_id="theone",
+        start=True,
+        flags=42,
+        audio_settings=audio_settings,
+    )
+    mock_data_received(protocol, generate_plaintext_packet(response))
+    await asyncio.sleep(0)
+    await asyncio.sleep(0)
+    unsub()
+    await asyncio.sleep(0)
+    assert not stops
+    assert starts == [
+        (
+            "theone",
+            42,
+            VoiceAssistantAudioSettingsModel(
+                noise_suppression_level=42,
+                auto_gain=42,
+                volume_multiplier=42,
+            ),
+        )
+    ]
+
+
 @pytest.mark.asyncio
 async def test_api_version_after_connection_closed(
     api_client: tuple[