Fix flaky dsmr tests broken by Python 3.14.3 asyncio changes (#169431)

tests/components/dsmr/conftest.py

@@ -25,6 +25,9 @@ def dsmr_connection_fixture() -> Generator[tuple[MagicMock, MagicMock, MagicMock
     transport = MagicMock(spec=asyncio.Transport)
     protocol = MagicMock(spec=DSMRProtocol)
 
+    closed = asyncio.Event()
+    protocol.wait_closed = closed.wait
+
     async def connection_factory(*args, **kwargs):
         """Return mocked out Asyncio classes."""
         return (transport, protocol)
@@ -42,6 +45,7 @@ def dsmr_connection_fixture() -> Generator[tuple[MagicMock, MagicMock, MagicMock
         ),
     ):
         yield (connection_factory, transport, protocol)
+        closed.set()
 
 
 @pytest.fixture
@@ -53,6 +57,9 @@ def rfxtrx_dsmr_connection_fixture() -> Generator[
     transport = MagicMock(spec=asyncio.Transport)
     protocol = MagicMock(spec=RFXtrxDSMRProtocol)
 
+    closed = asyncio.Event()
+    protocol.wait_closed = closed.wait
+
     async def connection_factory(*args, **kwargs):
         """Return mocked out Asyncio classes."""
         return (transport, protocol)
@@ -70,6 +77,7 @@ def rfxtrx_dsmr_connection_fixture() -> Generator[
         ),
     ):
         yield (connection_factory, transport, protocol)
+        closed.set()
 
 
 @pytest.fixture

tests/components/dsmr/test_diagnostics.py

@@ -10,7 +10,6 @@ from dsmr_parser.obis_references import (
     GAS_METER_READING,
 )
 from dsmr_parser.objects import CosemObject, MBusObject, Telegram
-import pytest
 from syrupy.assertion import SnapshotAssertion
 
 from homeassistant.core import HomeAssistant
@@ -20,9 +19,6 @@ from tests.components.diagnostics import get_diagnostics_for_config_entry
 from tests.typing import ClientSessionGenerator
 
 
-@pytest.mark.xfail(
-    reason="Flaky due to Python 3.14.3 asyncio changes - see home-assistant/core#162263"
-)
 async def test_diagnostics(
     hass: HomeAssistant,
     hass_client: ClientSessionGenerator,

tests/components/dsmr/test_sensor.py

@@ -51,9 +51,6 @@ from homeassistant.helpers import entity_registry as er
 from tests.common import MockConfigEntry, patch
 
 
-@pytest.mark.xfail(
-    reason="Flaky due to Python 3.14.3 asyncio changes - see home-assistant/core#162263"
-)
 async def test_default_setup(
     hass: HomeAssistant,
     entity_registry: er.EntityRegistry,