Fix auto marking of async hypothesis tests in auto mode (#259)

* refactor: Extracted function determining whether a test function is a Hypothesis test.

Signed-off-by: Michael Seifert <m.seifert@digitalernachschub.de>

* fix: Fixes a bug that prevents async Hypothesis tests from working without explicit "asyncio" marker when "--asyncio-mode=auto" is set.

The option --asyncio-mode=auto marks all async functions with the asyncio mark during the collection phase. However, when pytest collects the Hypothesis test, the @given decorator has already been applied and the Hypothesis test function is no longer a coroutine.

This commit extends the "pytest_pycollect_makeitem" hook to mark Hypothesis tests whose function body is a coroutine.

Closes #258

Signed-off-by: Michael Seifert <m.seifert@digitalernachschub.de>

README.rst

@@ -256,6 +256,10 @@ or an async framework such as `asynctest <https://asynctest.readthedocs.io/en/la
 
 Changelog
 ---------
+0.17.1 (UNRELEASED)
+~~~~~~~~~~~~~~~~~~~
+- Fixes a bug that prevents async Hypothesis tests from working without explicit ``asyncio`` marker when ``--asyncio-mode=auto`` is set. `#258 <https://github.com/pytest-dev/pytest-asyncio/issues/258>`_
+
 0.17.0 (22-01-13)
 ~~~~~~~~~~~~~~~~~~~
 - `pytest-asyncio` no longer alters existing event loop policies. `#168 <https://github.com/pytest-dev/pytest-asyncio/issues/168>`_, `#188 <https://github.com/pytest-dev/pytest-asyncio/issues/168>`_

pytest_asyncio/plugin.py

@@ -115,7 +115,13 @@ def pytest_configure(config):
 @pytest.mark.tryfirst
 def pytest_pycollect_makeitem(collector, name, obj):
     """A pytest hook to collect asyncio coroutines."""
-    if collector.funcnamefilter(name) and _is_coroutine(obj):
+    if not collector.funcnamefilter(name):
+        return
+    if (
+        _is_coroutine(obj)
+        or _is_hypothesis_test(obj)
+        and _hypothesis_test_wraps_coroutine(obj)
+    ):
         item = pytest.Function.from_parent(collector, name=name)
         if "asyncio" in item.keywords:
             return list(collector._genfunctions(name, obj))
@@ -128,6 +134,10 @@ def pytest_pycollect_makeitem(collector, name, obj):
                 return ret
 
 
+def _hypothesis_test_wraps_coroutine(function):
+    return _is_coroutine(function.hypothesis.inner_test)
+
+
 class FixtureStripper:
     """Include additional Fixture, and then strip them"""
 
@@ -288,7 +298,7 @@ def pytest_pyfunc_call(pyfuncitem):
     where the wrapped test coroutine is executed in an event loop.
     """
     if "asyncio" in pyfuncitem.keywords:
-        if getattr(pyfuncitem.obj, "is_hypothesis_test", False):
+        if _is_hypothesis_test(pyfuncitem.obj):
             pyfuncitem.obj.hypothesis.inner_test = wrap_in_sync(
                 pyfuncitem.obj.hypothesis.inner_test,
                 _loop=pyfuncitem.funcargs["event_loop"],
@@ -300,6 +310,10 @@ def pytest_pyfunc_call(pyfuncitem):
     yield
 
 
+def _is_hypothesis_test(function) -> bool:
+    return getattr(function, "is_hypothesis_test", False)
+
+
 def wrap_in_sync(func, _loop):
     """Return a sync wrapper around an async function executing it in the
     current event loop."""

tests/hypothesis/test_base.py

@@ -2,6 +2,7 @@
 sync shim for Hypothesis.
 """
 import asyncio
+from textwrap import dedent
 
 import pytest
 from hypothesis import given, strategies as st
@@ -40,3 +41,48 @@ async def test_can_use_fixture_provided_event_loop(event_loop, n):
     semaphore = asyncio.Semaphore(value=0)
     event_loop.call_soon(semaphore.release)
     await semaphore.acquire()
+
+
+def test_async_auto_marked(pytester):
+    pytester.makepyfile(
+        dedent(
+            """\
+        import asyncio
+        import pytest
+        from hypothesis import given
+        import hypothesis.strategies as st
+
+        pytest_plugins = 'pytest_asyncio'
+
+        @given(n=st.integers())
+        async def test_hypothesis(n: int):
+            assert isinstance(n, int)
+        """
+        )
+    )
+    result = pytester.runpytest("--asyncio-mode=auto")
+    result.assert_outcomes(passed=1)
+
+
+def test_sync_not_auto_marked(pytester):
+    """Assert that synchronous Hypothesis functions are not marked with asyncio"""
+    pytester.makepyfile(
+        dedent(
+            """\
+        import asyncio
+        import pytest
+        from hypothesis import given
+        import hypothesis.strategies as st
+
+        pytest_plugins = 'pytest_asyncio'
+
+        @given(n=st.integers())
+        def test_hypothesis(request, n: int):
+            markers = [marker.name for marker in request.node.own_markers]
+            assert "asyncio" not in markers
+            assert isinstance(n, int)
+        """
+        )
+    )
+    result = pytester.runpytest("--asyncio-mode=auto")
+    result.assert_outcomes(passed=1)