Mark async socket handling task done and implement startup cleanup

backend/tests/test_services/test_fail2ban_client.py

@@ -226,15 +226,10 @@ class TestFail2BanClientSend:
         """``send()`` must return the response from the executor."""
         expected = [0, "OK"]
         client = Fail2BanClient(socket_path="/fake/fail2ban.sock")
-        # asyncio.get_event_loop().run_in_executor is called inside send().
-        # We patch it on the loop object returned by asyncio.get_event_loop().
-        with patch("asyncio.get_event_loop") as mock_get_loop:
-            mock_loop = AsyncMock()
-            mock_loop.run_in_executor = AsyncMock(return_value=expected)
-            mock_get_loop.return_value = mock_loop
-
+        with patch("asyncio.to_thread", new_callable=AsyncMock, return_value=expected) as mock_to_thread:
             result = await client.send(["status"])
 
+        mock_to_thread.assert_awaited_once()
         assert result == expected
 
     @pytest.mark.asyncio
@@ -242,13 +237,11 @@ class TestFail2BanClientSend:
         """``send()`` must re-raise :class:`Fail2BanConnectionError`."""
         client = Fail2BanClient(socket_path="/fake/fail2ban.sock")
 
-        with patch("asyncio.get_event_loop") as mock_get_loop:
-            mock_loop = AsyncMock()
-            mock_loop.run_in_executor = AsyncMock(
-                side_effect=Fail2BanConnectionError("unreachable", "/fake/fail2ban.sock")
-            )
-            mock_get_loop.return_value = mock_loop
-
+        with patch(
+            "asyncio.to_thread",
+            new_callable=AsyncMock,
+            side_effect=Fail2BanConnectionError("unreachable", "/fake/fail2ban.sock"),
+        ):
             with pytest.raises(Fail2BanConnectionError):
                 await client.send(["status"])
 
@@ -257,13 +250,11 @@ class TestFail2BanClientSend:
         """``send()`` must log a warning when a connection error occurs."""
         client = Fail2BanClient(socket_path="/fake/fail2ban.sock")
 
-        with patch("asyncio.get_event_loop") as mock_get_loop:
-            mock_loop = AsyncMock()
-            mock_loop.run_in_executor = AsyncMock(
-                side_effect=Fail2BanConnectionError("refused", "/fake/fail2ban.sock")
-            )
-            mock_get_loop.return_value = mock_loop
-
+        with patch(
+            "asyncio.to_thread",
+            new_callable=AsyncMock,
+            side_effect=Fail2BanConnectionError("refused", "/fake/fail2ban.sock"),
+        ):
             with patch("app.utils.fail2ban_client.log") as mock_log, pytest.raises(Fail2BanConnectionError):
                 await client.send(["ping"])
 
@@ -278,13 +269,11 @@ class TestFail2BanClientSend:
         """``send()`` must re-raise :class:`Fail2BanProtocolError`."""
         client = Fail2BanClient(socket_path="/fake/fail2ban.sock")
 
-        with patch("asyncio.get_event_loop") as mock_get_loop:
-            mock_loop = AsyncMock()
-            mock_loop.run_in_executor = AsyncMock(
-                side_effect=Fail2BanProtocolError("bad pickle")
-            )
-            mock_get_loop.return_value = mock_loop
-
+        with patch(
+            "asyncio.to_thread",
+            new_callable=AsyncMock,
+            side_effect=Fail2BanProtocolError("bad pickle"),
+        ):
             with pytest.raises(Fail2BanProtocolError):
                 await client.send(["status"])
 
@@ -293,13 +282,11 @@ class TestFail2BanClientSend:
         """``send()`` must propagate :class:`Fail2BanProtocolError` to the caller."""
         client = Fail2BanClient(socket_path="/fake/fail2ban.sock")
 
-        with patch("asyncio.get_event_loop") as mock_get_loop:
-            mock_loop = AsyncMock()
-            mock_loop.run_in_executor = AsyncMock(
-                side_effect=Fail2BanProtocolError("bad pickle")
-            )
-            mock_get_loop.return_value = mock_loop
-
+        with patch(
+            "asyncio.to_thread",
+            new_callable=AsyncMock,
+            side_effect=Fail2BanProtocolError("bad pickle"),
+        ):
             with pytest.raises(Fail2BanProtocolError):
                 await client.send(["status"])
 
@@ -308,13 +295,11 @@ class TestFail2BanClientSend:
         """``send()`` must log an error when a protocol error occurs."""
         client = Fail2BanClient(socket_path="/fake/fail2ban.sock")
 
-        with patch("asyncio.get_event_loop") as mock_get_loop:
-            mock_loop = AsyncMock()
-            mock_loop.run_in_executor = AsyncMock(
-                side_effect=Fail2BanProtocolError("corrupt response")
-            )
-            mock_get_loop.return_value = mock_loop
-
+        with patch(
+            "asyncio.to_thread",
+            new_callable=AsyncMock,
+            side_effect=Fail2BanProtocolError("corrupt response"),
+        ):
             with patch("app.utils.fail2ban_client.log") as mock_log, pytest.raises(Fail2BanProtocolError):
                 await client.send(["get", "sshd", "banned"])
 
@@ -492,11 +477,7 @@ class TestFail2BanClientSemaphore:
             in_flight.pop()
             return (0, "ok")
 
-        with patch("asyncio.get_event_loop") as mock_loop_getter:
-            mock_loop = MagicMock()
-            mock_loop.run_in_executor = _fast_executor
-            mock_loop_getter.return_value = mock_loop
-
+        with patch("asyncio.to_thread", new=_fast_executor):
             tasks = [
                 _asyncio.create_task(client.send(["ping"])) for _ in range(10)
             ]