Scoped event loops based on pytest marks #620
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…coped asyncio event loop when a class has the mark. Signed-off-by: Michael Seifert <[email protected]>
…est.Pytester to avoid applying pytestmark to subsequent tests in the test module. Signed-off-by: Michael Seifert <[email protected]>
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Codecov ReportAttention:
Additional details and impacted files@@ Coverage Diff @@
## main #620 +/- ##
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- Coverage 93.95% 93.49% -0.46%
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Files 2 2
Lines 281 338 +57
Branches 55 70 +15
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+ Hits 264 316 +52
- Misses 11 12 +1
- Partials 6 10 +4
☔ View full report in Codecov by Sentry. |
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Added support for module-scoped loops. |
…vent loop when a module has the mark. Signed-off-by: Michael Seifert <[email protected]>
…nt loop implementation to pollute the test environment. Signed-off-by: Michael Seifert <[email protected]>
…event loop implementation from polluting the test environment. Signed-off-by: Michael Seifert <[email protected]>
…tor tests no longer requires an explicit event loop argument. The wrapper retrieves the currently set loop via asyncio.get_event_loop, instead. Signed-off-by: Michael Seifert <[email protected]>
…the function-scoped event_loop fixture. They rather provide a fixture with a different name, based on the nodeid of the pytest.Collector that has the "asyncio_event_loop" mark. When a test requests the event_loop fixture and a dynamically generated event loop with class or module scope, pytest-asyncio will raise an error. Signed-off-by: Michael Seifert <[email protected]>
…p inside the event_loop fixture override rather than on the module-level. This prevents the custom loop from being created during test collection time. Signed-off-by: Michael Seifert <[email protected]>
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Added support for specifying a single event loop policy as a keyword argument to the |
…policy. Signed-off-by: Michael Seifert <[email protected]>
…sing an iterable of policies. This causes tests under the _asyncio_event_loop_ mark to be parametrized with the different loop policies. Signed-off-by: Michael Seifert <[email protected]>
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…e executed in the same event loop. Signed-off-by: Michael Seifert <[email protected]>
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Signed-off-by: Michael Seifert <[email protected]>
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I decided to move the deprecation of the event loop fixture into a separate PR. |
Signed-off-by: Michael Seifert <[email protected]>
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This was referenced Oct 22, 2023
This was referenced Oct 23, 2023
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This PR introduces the asyncio_event_loop mark. When applied to classes and modules, the mark provides an asyncio event loop that is class-scoped or module-scoped, respectively. This is a prerequisite for the deprecation of event_loop fixture overrides (see #631).
Fixtures and tests under the same asyncio_event_loop mark are run in the same event loop, thus addressing #127 in parts.
The asyncio_event_loop mark supports an optional
policykeyword argument, which takes an event loop policy or an iterable of policies. Tests under the effect of the mark are parametrized over the provided policies. If no policy is provided, the mark falls back to the value ofasyncio.get_event_loop_policy()at mark definition time. This functionality offers a workaround for #591.The implementation dynamically creates pytest fixtures based on the presence of the asycnio_event_loop mark. The fixtures are anchored at the corresponding module or class. The generated fixtures have a unique name that is generated from the pytest node ID of the module or class.
The generated fixtures are always parametrized, even when just a single event loop policy is specified. Therefore, we need to make pytest aware which parameters to use when evaluating the fixture. This happens in
pytest_generate_tests. Whenever pytest_generate_tests is called for a test that is affected by an asyncio_event_loop mark_, the name of the dynamic fixture is injected into the metafunc along with the dynamic fixture definition. This information allows pytest to perform the standard fixture parametrization.There is one special case, where a user may have requested the
event_loopfixture for an async test that also requests a scoped event loop. In this case, the code raises an error, because we cannot possibly know what the user intended to do here.