fix: Fixed double wrapping of inherited Hypothesis tests.

Pytest-asyncio identifies Hypothesis test cases by their `is_hypothesis_test` flag. When setting up an async Hypothesis test pytest-asyncio replaces wraps function's `hypothesis.inner_test` attribute. The the top level function never changes.

When a Hypothesis test case is defined in a base class and inherited by subclasses, the test is collected in each subclass. Since the top-level Hypothesis test never changes, its inner test will be wrapped multiple times.

Double wrapping leads to execution errors caused by stale (closed) event loops in all test executions after the first.

This change adds an `original_test_function` attribute to the async function wrapper, in order to keep track of the original Hypothesis test. When re-wrapping would occur in subclasses pytest-asyncio wraps the original test function rather than the wrapper function.

Closes pytest-dev#231

Signed-off-by: Michael Seifert <[email protected]>

Author: seifertm

README.rst

@@ -175,6 +175,7 @@ Changelog
 ~~~~~~~~~~~~~~~~~~~
 - `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>`_
 - Drop support for Python 3.6
+- Fixed an issue that prevented inherited asynchronous Hypothesis tests from working. `#231 <https://github.com/pytest-dev/pytest-asyncio/issues/231>`_
 
 0.16.0 (2021-10-16)
 ~~~~~~~~~~~~~~~~~~~

pytest_asyncio/plugin.py

@@ -158,10 +158,16 @@ def pytest_pyfunc_call(pyfuncitem):
     """
     if "asyncio" in pyfuncitem.keywords:
         if getattr(pyfuncitem.obj, "is_hypothesis_test", False):
-            pyfuncitem.obj.hypothesis.inner_test = wrap_in_sync(
+            hypothesis_inner_test = getattr(
                 pyfuncitem.obj.hypothesis.inner_test,
+                "original_test_function",
+                pyfuncitem.obj.hypothesis.inner_test,
+            )
+            synchronous_test_function = wrap_in_sync(
+                hypothesis_inner_test,
                 _loop=pyfuncitem.funcargs["event_loop"],
             )
+            pyfuncitem.obj.hypothesis.inner_test = synchronous_test_function
         else:
             pyfuncitem.obj = wrap_in_sync(
                 pyfuncitem.obj, _loop=pyfuncitem.funcargs["event_loop"]
@@ -188,6 +194,8 @@ def inner(**kwargs):
                     task.exception()
                 raise
 
+    inner.original_test_function = func
+
     return inner
 
 

tests/hypothesis/test_inherited_test.py

@@ -0,0 +1,22 @@
+import hypothesis.strategies as st
+from hypothesis import given
+import pytest
+
+
+class BaseClass:
+    @pytest.mark.asyncio
+    @given(value=st.integers())
+    async def test_hypothesis(self, value: int) -> None:
+        assert True
+
+
+class TestOne(BaseClass):
+    """During the first execution the Hypothesis test is wrapped in a synchronous function."""
+
+    pass
+
+
+class TestTwo(BaseClass):
+    """Execute the test a second time to ensure that the test receives a fresh event loop."""
+
+    pass