Do not try to initialize async fixtures without explicit asyncio mark in strict mode

CHANGELOG.rst

@@ -2,6 +2,11 @@
 Changelog
 =========
 
+UNRELEASED
+=================
+- Adds `pytest-trio <https://pypi.org/project/pytest-trio/>`_ to the test dependencies
+- Fixes a bug that caused pytest-asyncio to try to set up async pytest_trio fixtures in strict mode. `#298 <https://github.com/pytest-dev/pytest-asyncio/issues/298>`_
+
 0.18.2 (22-03-03)
 =================
 - Fix asyncio auto mode not marking static methods. `#295 <https://github.com/pytest-dev/pytest-asyncio/issues/295>`_

pytest_asyncio/plugin.py

@@ -210,7 +210,11 @@ def _preprocess_async_fixtures(config: Config, holder: Set[FixtureDef]) -> None:
                 # Nothing to do with a regular fixture function
                 continue
             if not _has_explicit_asyncio_mark(func):
-                if asyncio_mode == Mode.AUTO:
+                if asyncio_mode == Mode.STRICT:
+                    # Ignore async fixtures without explicit asyncio mark in strict mode
+                    # This applies to pytest_trio fixtures, for example
+                    continue
+                elif asyncio_mode == Mode.AUTO:
                     # Enforce asyncio mode if 'auto'
                     _set_explicit_asyncio_mark(func)
                 elif asyncio_mode == Mode.LEGACY:

setup.cfg

@@ -44,6 +44,7 @@ testing =
   hypothesis >= 5.7.1
   flaky >= 3.5.0
   mypy == 0.931
+  pytest-trio >= 0.7.0
 
 [options.entry_points]
 pytest11 =

tests/sessionloop/conftest.py → tests/loop_fixture_scope/conftest.py

@@ -3,14 +3,14 @@
 import pytest
 
 
-class CustomSelectorLoopSession(asyncio.SelectorEventLoop):
+class CustomSelectorLoop(asyncio.SelectorEventLoop):
     """A subclass with no overrides, just to test for presence."""
 
 
-loop = CustomSelectorLoopSession()
+loop = CustomSelectorLoop()
 
 
-@pytest.fixture(scope="package")
+@pytest.fixture(scope="module")
 def event_loop():
     """Create an instance of the default event loop for each test case."""
     yield loop

tests/sessionloop/test_session_loops.py → tests/loop_fixture_scope/test_loop_fixture_scope.py

@@ -1,4 +1,4 @@
-"""Unit tests for overriding the event loop with a session scoped one."""
+"""Unit tests for overriding the event loop with a larger scoped one."""
 import asyncio
 
 import pytest
@@ -8,7 +8,7 @@
 async def test_for_custom_loop():
     """This test should be executed using the custom loop."""
     await asyncio.sleep(0.01)
-    assert type(asyncio.get_event_loop()).__name__ == "CustomSelectorLoopSession"
+    assert type(asyncio.get_event_loop()).__name__ == "CustomSelectorLoop"
 
 
 @pytest.mark.asyncio

tests/test_subprocess.py

@@ -15,17 +15,20 @@ def event_loop():
         loop.close()
 
 
-@pytest.mark.asyncio(forbid_global_loop=False)
-async def test_subprocess(event_loop):
-    """Starting a subprocess should be possible."""
-    proc = await asyncio.subprocess.create_subprocess_exec(
-        sys.executable, "--version", stdout=asyncio.subprocess.PIPE
-    )
-    await proc.communicate()
+@pytest.mark.skipif(
+    sys.version_info < (3, 8),
+    reason="""
+        When run with Python 3.7 asyncio.subprocess.create_subprocess_exec seems to be
+        affected by an issue that prevents correct cleanup. Tests using pytest-trio
+        will report that signal handling is already performed by another library and
+        fail. [1] This is possibly a bug in CPython 3.7, so we ignore this test for
+        that Python version.
 
-
-@pytest.mark.asyncio(forbid_global_loop=True)
-async def test_subprocess_forbid(event_loop):
+        [1] https://github.com/python-trio/pytest-trio/issues/126
+    """,
+)
+@pytest.mark.asyncio
+async def test_subprocess(event_loop):
     """Starting a subprocess should be possible."""
     proc = await asyncio.subprocess.create_subprocess_exec(
         sys.executable, "--version", stdout=asyncio.subprocess.PIPE

tests/trio/test_fixtures.py

@@ -0,0 +1,25 @@
+from textwrap import dedent
+
+
+def test_strict_mode_ignores_trio_fixtures(testdir):
+    testdir.makepyfile(
+        dedent(
+            """\
+        import pytest
+        import pytest_asyncio
+        import pytest_trio
+
+        pytest_plugins = ["pytest_asyncio", "pytest_trio"]
+
+        @pytest_trio.trio_fixture
+        async def any_fixture():
+            return True
+
+        @pytest.mark.trio
+        async def test_anything(any_fixture):
+            pass
+        """
+        )
+    )
+    result = testdir.runpytest("--asyncio-mode=strict")
+    result.assert_outcomes(passed=1)