python-zeroconf
diff --git a/.gitignore b/.gitignore
@@ -18,3 +18,4 @@ docs/_build/
 /dist/
 /zeroconf.egg-info/
 /src/**/*.c
+.hypothesis/
diff --git a/poetry.lock b/poetry.lock
diff --git a/pyproject.toml b/pyproject.toml
@@ -92,6 +92,7 @@ setuptools = ">=83.0.0,<84.0.0"
 pytest-timeout = "^2.1.0"
 pytest-codspeed = ">=5.0.3,<6.0"
 blockbuster = ">=1.5.27,<2.0.0"
+hypothesis = {version = "^6.165.10", markers = "implementation_name == 'cpython'"}
 
 [tool.poetry.group.docs.dependencies]
 sphinx = "^7.4.7 || ^8.1.3"

diff --git a/tests/conftest.py b/tests/conftest.py
@@ -2,6 +2,8 @@
 
 from __future__ import annotations
 
+import importlib.util
+import os
 import threading
 from collections.abc import AsyncGenerator, Generator, Iterator
 from unittest.mock import patch
@@ -15,6 +17,20 @@
 from zeroconf._services import info as service_info
 from zeroconf.asyncio import AsyncZeroconf
 
+# The dev dependency group only installs hypothesis on CPython (the CI
+# matrix pins pypy-3.10 and hypothesis ships no pp310 wheels), and a
+# non-dev install has no hypothesis at all.
+collect_ignore: list[str] = []
+if importlib.util.find_spec("hypothesis") is None:
+    collect_ignore.append("test_fuzz_incoming.py")
+else:
+    from hypothesis import settings as _hypothesis_settings
+
+    # Deterministic in CI; set HYPOTHESIS_PROFILE=long for a deep local run.
+    _hypothesis_settings.register_profile("ci", derandomize=True, max_examples=200, deadline=None)
+    _hypothesis_settings.register_profile("long", max_examples=50000, deadline=None)
+    _hypothesis_settings.load_profile(os.environ.get("HYPOTHESIS_PROFILE", "ci"))
+
 try:
     from blockbuster import BlockBuster, blockbuster_ctx
 except ImportError:  # platforms without blockbuster (e.g. PyPy under QEMU)