mirror of https://github.com/pypa/pip
74 lines
2.3 KiB
Python
74 lines
2.3 KiB
Python
"""Test multiprocessing/multithreading higher-order functions."""
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from contextlib import contextmanager
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from importlib import import_module
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from math import factorial
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from sys import modules
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from typing import Any, Iterator
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import pytest
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DUNDER_IMPORT = "builtins.__import__"
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FUNC, ITERABLE = factorial, range(42)
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MAPS = "map_multiprocess", "map_multithread"
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_import = __import__
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def unload_parallel() -> None:
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try:
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del modules["pip._internal.utils.parallel"]
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except KeyError:
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pass
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@contextmanager
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def tmp_import_parallel() -> Iterator[Any]:
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unload_parallel()
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try:
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yield import_module("pip._internal.utils.parallel")
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finally:
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unload_parallel()
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def lack_sem_open(name: str, *args: Any, **kwargs: Any) -> Any:
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"""Raise ImportError on import of multiprocessing.synchronize."""
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if name.endswith("synchronize"):
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raise ImportError
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return _import(name, *args, **kwargs)
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def have_sem_open(name: str, *args: Any, **kwargs: Any) -> Any:
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"""Make sure multiprocessing.synchronize import is successful."""
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# We don't care about the return value
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# since we don't use the pool with this import.
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if name.endswith("synchronize"):
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return None
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return _import(name, *args, **kwargs)
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@pytest.mark.parametrize("name", MAPS)
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def test_lack_sem_open(name: str, monkeypatch: pytest.MonkeyPatch) -> None:
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"""Test fallback when sem_open is not available.
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If so, multiprocessing[.dummy].Pool will fail to be created and
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map_async should fallback to map.
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"""
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monkeypatch.setattr(DUNDER_IMPORT, lack_sem_open)
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with tmp_import_parallel() as parallel:
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assert getattr(parallel, name) is parallel._map_fallback
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@pytest.mark.parametrize("name", MAPS)
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def test_have_sem_open(name: str, monkeypatch: pytest.MonkeyPatch) -> None:
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"""Test fallback when sem_open is available."""
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monkeypatch.setattr(DUNDER_IMPORT, have_sem_open)
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with tmp_import_parallel() as parallel:
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assert getattr(parallel, name) is getattr(parallel, f"_{name}")
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@pytest.mark.parametrize("name", MAPS)
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def test_map(name: str) -> None:
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"""Test correctness of result of asynchronous maps."""
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map_async = getattr(import_module("pip._internal.utils.parallel"), name)
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assert set(map_async(FUNC, ITERABLE)) == set(map(FUNC, ITERABLE))
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