python-zeroconf · bdraco · May 20, 2026 · May 20, 2026
diff --git a/tests/__init__.py b/tests/__init__.py
@@ -26,12 +26,13 @@
 import platform
 import socket
 import time
+from collections.abc import Iterable
 from functools import cache
 from unittest import mock
 
 import ifaddr
 
-from zeroconf import DNSIncoming, DNSQuestion, DNSRecord, Zeroconf
+from zeroconf import DNSIncoming, DNSOutgoing, DNSQuestion, DNSRecord, Zeroconf, const
 from zeroconf._history import QuestionHistory
 
 _MONOTONIC_RESOLUTION = time.get_clock_info("monotonic").resolution
@@ -70,6 +71,14 @@ def suppresses(self, question: DNSQuestion, now: float, known_answers: set[DNSRe
         return False
 
 
+def mock_incoming_msg(records: Iterable[DNSRecord]) -> DNSIncoming:
+    """Build a `DNSIncoming` response message from a list of `DNSRecord`s."""
+    generated = DNSOutgoing(const._FLAGS_QR_RESPONSE)
+    for record in records:
+        generated.add_answer_at_time(record, 0)
+    return DNSIncoming(generated.packets()[0])
+
+
 def _inject_responses(zc: Zeroconf, msgs: list[DNSIncoming]) -> None:
     """Inject a DNSIncoming response."""
     assert zc.loop is not None

diff --git a/tests/conftest.py b/tests/conftest.py
@@ -3,15 +3,17 @@
 from __future__ import annotations
 
 import threading
-from collections.abc import Generator
+from collections.abc import AsyncGenerator, Generator
 from unittest.mock import patch
 
 import pytest
+import pytest_asyncio
 
-from zeroconf import _core, const
+from zeroconf import Zeroconf, _core, const
 from zeroconf._handlers import query_handler
 from zeroconf._services import browser as service_browser
 from zeroconf._services import info as service_info
+from zeroconf.asyncio import AsyncZeroconf
 
 
 @pytest.fixture(autouse=True)
@@ -23,6 +25,36 @@ def verify_threads_ended():
     assert not threads
 
 
+@pytest.fixture
+def zc_loopback() -> Generator[Zeroconf]:
+    """Yield a loopback `Zeroconf` and close it on teardown.
+
+    Replaces the inline `zc = Zeroconf(interfaces=["127.0.0.1"])` +
+    explicit `zc.close()` pattern duplicated across the suite. Calling
+    `zc.close()` inside a test is still safe — `close()` is idempotent.
+    """
+    zc = Zeroconf(interfaces=["127.0.0.1"])
+    try:
+        yield zc
+    finally:
+        zc.close()
+
+
+@pytest_asyncio.fixture
+async def aiozc_loopback() -> AsyncGenerator[AsyncZeroconf]:
+    """Yield a loopback `AsyncZeroconf` and close it on teardown.
+
+    Replaces the inline `aiozc = AsyncZeroconf(interfaces=["127.0.0.1"])`
+    + explicit `await aiozc.async_close()` pattern duplicated across the
+    suite. Calling `async_close()` inside a test is still safe.
+    """
+    aiozc = AsyncZeroconf(interfaces=["127.0.0.1"])
+    try:
+        yield aiozc
+    finally:
+        await aiozc.async_close()
+
+
 @pytest.fixture
 def run_isolated():
     """Change the mDNS port to run the test in isolation."""

diff --git a/tests/services/test_browser.py b/tests/services/test_browser.py
@@ -8,7 +8,6 @@
 import socket
 import time
 import unittest
-from collections.abc import Iterable
 from threading import Event
 from typing import cast
 from unittest.mock import patch
@@ -36,6 +35,7 @@
     _inject_response,
     _wait_for_start,
     has_working_ipv6,
+    mock_incoming_msg,
     time_changed_millis,
 )
 
@@ -54,13 +54,6 @@ def teardown_module():
         log.setLevel(original_logging_level)
 
 
-def mock_incoming_msg(records: Iterable[r.DNSRecord]) -> r.DNSIncoming:
-    generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
-    for record in records:
-        generated.add_answer_at_time(record, 0)
-    return r.DNSIncoming(generated.packets()[0])
-
-
 def test_service_browser_cancel_multiple_times():
     """Test we can cancel a ServiceBrowser multiple times before close."""
 

diff --git a/tests/services/test_info.py b/tests/services/test_info.py
@@ -8,7 +8,6 @@
 import socket
 import threading
 import unittest
-from collections.abc import Iterable
 from ipaddress import ip_address
 from threading import Event
 from unittest.mock import patch
@@ -23,7 +22,7 @@
 from zeroconf._utils.net import IPVersion
 from zeroconf.asyncio import AsyncZeroconf
 
-from .. import QUICK_REQUEST_TIMEOUT_MS, _inject_response, has_working_ipv6
+from .. import QUICK_REQUEST_TIMEOUT_MS, _inject_response, has_working_ipv6, mock_incoming_msg
 
 log = logging.getLogger("zeroconf")
 original_logging_level = logging.NOTSET
@@ -279,14 +278,6 @@ def send(out, addr=const._MDNS_ADDR, port=const._MDNS_PORT, v6_flow_scope=()):
         # patch the zeroconf send
         with patch.object(zc, "async_send", send):
 
-            def mock_incoming_msg(records: Iterable[r.DNSRecord]) -> r.DNSIncoming:
-                generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
-
-                for record in records:
-                    generated.add_answer_at_time(record, 0)
-
-                return r.DNSIncoming(generated.packets()[0])
-
             def get_service_info_helper(zc, type, name):
                 nonlocal service_info
                 service_info = zc.get_service_info(type, name)
@@ -422,14 +413,6 @@ def send(out, addr=const._MDNS_ADDR, port=const._MDNS_PORT, v6_flow_scope=()):
         # patch the zeroconf send
         with patch.object(zc, "async_send", send):
 
-            def mock_incoming_msg(records: Iterable[r.DNSRecord]) -> r.DNSIncoming:
-                generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
-
-                for record in records:
-                    generated.add_answer_at_time(record, 0)
-
-                return r.DNSIncoming(generated.packets()[0])
-
             def get_service_info_helper(zc, type, name, timeout):
                 nonlocal service_info
                 service_info = zc.get_service_info(type, name, timeout)
@@ -552,12 +535,6 @@ def test_get_info_single(self):
             ),
         ]
 
-        def mock_incoming_msg(records: Iterable[r.DNSRecord]) -> r.DNSIncoming:
-            generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
-            for record in records:
-                generated.add_answer_at_time(record, 0)
-            return r.DNSIncoming(generated.packets()[0])
-
         sent_queries: list[r.DNSOutgoing] = []
 
         def send(out, addr=const._MDNS_ADDR, port=const._MDNS_PORT, v6_flow_scope=()):

diff --git a/tests/test_engine.py b/tests/test_engine.py
@@ -74,39 +74,31 @@ async def test_reaper():
 
 
 @pytest.mark.asyncio
-async def test_setup_releases_socket_ownership() -> None:
+async def test_setup_releases_socket_ownership(aiozc_loopback: AsyncZeroconf) -> None:
     """Engine releases its pending-socket refs once each socket has a transport."""
-    aiozc = AsyncZeroconf(interfaces=["127.0.0.1"])
-    try:
-        await aiozc.zeroconf.async_wait_for_start()
-        engine = aiozc.zeroconf.engine
-        assert engine._listen_socket is None
-        assert engine._respond_sockets == []
-        assert engine.readers
-        assert engine.senders
-    finally:
-        await aiozc.async_close()
+    await aiozc_loopback.zeroconf.async_wait_for_start()
+    engine = aiozc_loopback.zeroconf.engine
+    assert engine._listen_socket is None
+    assert engine._respond_sockets == []
+    assert engine.readers
+    assert engine.senders
 
 
 @pytest.mark.asyncio
-async def test_async_close_propagates_outer_cancellation() -> None:
+async def test_async_close_propagates_outer_cancellation(aiozc_loopback: AsyncZeroconf) -> None:
     """Outer-task cancellation while awaiting setup propagates to the caller."""
-    aiozc = AsyncZeroconf(interfaces=["127.0.0.1"])
+    await aiozc_loopback.zeroconf.async_wait_for_start()
+    engine = aiozc_loopback.zeroconf.engine
+    loop = asyncio.get_running_loop()
+    original_task = engine._setup_task
+    fake_task = loop.create_future()
+    fake_task.set_exception(asyncio.CancelledError())
+    engine._setup_task = fake_task  # type: ignore[assignment]
     try:
-        await aiozc.zeroconf.async_wait_for_start()
-        engine = aiozc.zeroconf.engine
-        loop = asyncio.get_running_loop()
-        original_task = engine._setup_task
-        fake_task = loop.create_future()
-        fake_task.set_exception(asyncio.CancelledError())
-        engine._setup_task = fake_task  # type: ignore[assignment]
-        try:
-            with pytest.raises(asyncio.CancelledError):
-                await engine._async_close()
-        finally:
-            engine._setup_task = original_task
+        with pytest.raises(asyncio.CancelledError):
+            await engine._async_close()
     finally:
-        await aiozc.async_close()
+        engine._setup_task = original_task
 
 
 @pytest.mark.asyncio