feat: Check marker arguments

docs: Added changelog entry for error for positional asyncio marker arguments.

Author: Cito

docs/source/reference/changelog.rst

@@ -6,6 +6,7 @@ Changelog
 ===================
 - Adds an optional `loop_scope` keyword argument to `pytest.mark.asyncio`. This argument controls which event loop is used to run the marked async test. `#706`_, `#871 <https://github.com/pytest-dev/pytest-asyncio/pull/871>`_
 - Deprecates the optional `scope` keyword argument to `pytest.mark.asyncio` for API consistency with ``pytest_asyncio.fixture``. Users are encouraged to use the `loop_scope` keyword argument, which does exactly the same.
+- Raises an error when passing `scope` or `loop_scope` as a positional argument to ``@pytest.mark.asyncio``. `#812 <https://github.com/pytest-dev/pytest-asyncio/issues/812>`_
 
 
 0.23.8 (2024-07-17)

pytest_asyncio/plugin.py

@@ -1004,6 +1004,10 @@ def pytest_runtest_setup(item: pytest.Item) -> None:
 
 def _get_marked_loop_scope(asyncio_marker: Mark) -> _ScopeName:
     assert asyncio_marker.name == "asyncio"
+    if asyncio_marker.args or (
+        asyncio_marker.kwargs and set(asyncio_marker.kwargs) - {"loop_scope", "scope"}
+    ):
+        raise ValueError("mark.asyncio accepts only a keyword argument 'scope'.")
     if "scope" in asyncio_marker.kwargs:
         if "loop_scope" in asyncio_marker.kwargs:
             raise pytest.UsageError(_DUPLICATE_LOOP_SCOPE_DEFINITION_ERROR)

tests/markers/test_invalid_arguments.py

@@ -0,0 +1,85 @@
+from textwrap import dedent
+
+import pytest
+
+
+def test_no_error_when_scope_passed_as_sole_keyword_argument(
+    pytester: pytest.Pytester,
+):
+    pytester.makepyfile(
+        dedent(
+            """\
+            import pytest
+
+            @pytest.mark.asyncio(loop_scope="session")
+            async def test_anything():
+                pass
+            """
+        )
+    )
+    result = pytester.runpytest_subprocess()
+    result.assert_outcomes(passed=1)
+    result.stdout.no_fnmatch_line("*ValueError*")
+
+
+def test_error_when_scope_passed_as_positional_argument(
+    pytester: pytest.Pytester,
+):
+    pytester.makepyfile(
+        dedent(
+            """\
+            import pytest
+
+            @pytest.mark.asyncio("session")
+            async def test_anything():
+                pass
+            """
+        )
+    )
+    result = pytester.runpytest_subprocess()
+    result.assert_outcomes(errors=1)
+    result.stdout.fnmatch_lines(
+        ["*ValueError: mark.asyncio accepts only a keyword argument*"]
+    )
+
+
+def test_error_when_wrong_keyword_argument_is_passed(
+    pytester: pytest.Pytester,
+):
+    pytester.makepyfile(
+        dedent(
+            """\
+            import pytest
+
+            @pytest.mark.asyncio(cope="session")
+            async def test_anything():
+                pass
+            """
+        )
+    )
+    result = pytester.runpytest_subprocess()
+    result.assert_outcomes(errors=1)
+    result.stdout.fnmatch_lines(
+        ["*ValueError: mark.asyncio accepts only a keyword argument 'scope'*"]
+    )
+
+
+def test_error_when_additional_keyword_arguments_are_passed(
+    pytester: pytest.Pytester,
+):
+    pytester.makepyfile(
+        dedent(
+            """\
+            import pytest
+
+            @pytest.mark.asyncio(loop_scope="session", more="stuff")
+            async def test_anything():
+                pass
+            """
+        )
+    )
+    result = pytester.runpytest_subprocess()
+    result.assert_outcomes(errors=1)
+    result.stdout.fnmatch_lines(
+        ["*ValueError: mark.asyncio accepts only a keyword argument*"]
+    )