[fix] Fixed a bug that causes markers to be duplicated for async test…

… functions.

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

docs/source/reference/changelog.rst

@@ -2,6 +2,15 @@
 Changelog
 =========
 
+0.23.8 (UNRELEASED)
+===================
+- Fixes a bug that caused duplicate markers in async tests `#813 <https://github.com/pytest-dev/pytest-asyncio/issues/813>`_
+
+Known issues
+------------
+As of v0.23, pytest-asyncio attaches an asyncio event loop to each item of the test suite (i.e. session, packages, modules, classes, functions) and allows tests to be run in those loops when marked accordingly. Pytest-asyncio currently assumes that async fixture scope is correlated with the new event loop scope. This prevents fixtures from being evaluated independently from the event loop scope and breaks some existing test suites (see `#706`_). For example, a test suite may require all fixtures and tests to run in the same event loop, but have async fixtures that are set up and torn down for each module. If you're affected by this issue, please continue using the v0.21 release, until it is resolved.
+
+
 0.23.7 (2024-05-19)
 ===================
 - Silence deprecation warnings about unclosed event loops that occurred with certain CPython patch releases `#817 <https://github.com/pytest-dev/pytest-asyncio/pull/817>`_

pytest_asyncio/plugin.py

@@ -405,7 +405,8 @@ def _from_function(cls, function: Function, /) -> Function:
             keywords=function.keywords,
             originalname=function.originalname,
         )
-        subclass_instance.own_markers.extend(function.own_markers)
+        subclass_instance.own_markers = function.own_markers
+        assert subclass_instance.own_markers == function.own_markers
         subclassed_function_signature = inspect.signature(subclass_instance.obj)
         if "event_loop" in subclassed_function_signature.parameters:
             subclass_instance.warn(

tests/markers/test_function_scope.py

@@ -197,3 +197,34 @@ async def test_anything():
     )
     result = pytester.runpytest_subprocess("--asyncio-mode=strict")
     result.assert_outcomes(warnings=0, passed=1)
+
+
+def test_asyncio_mark_does_not_duplicate_other_marks_in_auto_mode(
+    pytester: Pytester,
+):
+    pytester.makeconftest(
+        dedent(
+            """\
+            def pytest_configure(config):
+                config.addinivalue_line(
+                    "markers", "dummy_marker: mark used for testing purposes"
+                )
+            """
+        )
+    )
+    pytester.makepyfile(
+        dedent(
+            """\
+            import pytest
+
+            @pytest.mark.dummy_marker
+            async def test_markers_not_duplicated(request):
+                markers = []
+                for node, marker in request.node.iter_markers_with_node():
+                    markers.append(marker)
+                assert len(markers) == 2
+            """
+        )
+    )
+    result = pytester.runpytest_subprocess("--asyncio-mode=auto")
+    result.assert_outcomes(warnings=0, passed=1)