cpython/Lib/test/test_zoneinfo/_support.py

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bpo-40503: PEP 615: Tests and implementation for zoneinfo (GH-19909) This is the initial implementation of PEP 615, the zoneinfo module, ported from the standalone reference implementation (see https://www.python.org/dev/peps/pep-0615/#reference-implementation for a link, which has a more detailed commit history). This includes (hopefully) all functional elements described in the PEP, but documentation is found in a separate PR. This includes: 1. A pure python implementation of the ZoneInfo class 2. A C accelerated implementation of the ZoneInfo class 3. Tests with 100% branch coverage for the Python code (though C code coverage is less than 100%). 4. A compile-time configuration option on Linux (though not on Windows) Differences from the reference implementation: - The module is arranged slightly differently: the accelerated module is `_zoneinfo` rather than `zoneinfo._czoneinfo`, which also necessitates some changes in the test support function. (Suggested by Victor Stinner and Steve Dower.) - The tests are arranged slightly differently and do not include the property tests. The tests live at test/test_zoneinfo/test_zoneinfo.py rather than test/test_zoneinfo.py or test/test_zoneinfo/__init__.py because we may do some refactoring in the future that would likely require this separation anyway; we may: - include the property tests - automatically run all the tests against both pure Python and C, rather than manually constructing C and Python test classes (similar to the way this works with test_datetime.py, which generates C and Python test cases from datetimetester.py). - This includes a compile-time configuration option on Linux (though not on Windows); added with much help from Thomas Wouters. - Integration into the CPython build system is obviously different from building a standalone zoneinfo module wheel. - This includes configuration to install the tzdata package as part of CI, though only on the coverage jobs. Introducing a PyPI dependency as part of the CI build was controversial, and this is seen as less of a major change, since the coverage jobs already depend on pip and PyPI. Additional changes that were introduced as part of this PR, most / all of which were backported to the reference implementation: - Fixed reference and memory leaks With much debugging help from Pablo Galindo - Added smoke tests ensuring that the C and Python modules are built The import machinery can be somewhat fragile, and the "seamlessly falls back to pure Python" nature of this module makes it so that a problem building the C extension or a failure to import the pure Python version might easily go unnoticed. - Adjustments to zoneinfo.__dir__ Suggested by Petr Viktorin. - Slight refactorings as suggested by Steve Dower. - Removed unnecessary if check on std_abbr Discovered this because of a missing line in branch coverage.
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import contextlib
import functools
import sys
import threading
import unittest
from test.support.import_helper import import_fresh_module
bpo-40503: PEP 615: Tests and implementation for zoneinfo (GH-19909) This is the initial implementation of PEP 615, the zoneinfo module, ported from the standalone reference implementation (see https://www.python.org/dev/peps/pep-0615/#reference-implementation for a link, which has a more detailed commit history). This includes (hopefully) all functional elements described in the PEP, but documentation is found in a separate PR. This includes: 1. A pure python implementation of the ZoneInfo class 2. A C accelerated implementation of the ZoneInfo class 3. Tests with 100% branch coverage for the Python code (though C code coverage is less than 100%). 4. A compile-time configuration option on Linux (though not on Windows) Differences from the reference implementation: - The module is arranged slightly differently: the accelerated module is `_zoneinfo` rather than `zoneinfo._czoneinfo`, which also necessitates some changes in the test support function. (Suggested by Victor Stinner and Steve Dower.) - The tests are arranged slightly differently and do not include the property tests. The tests live at test/test_zoneinfo/test_zoneinfo.py rather than test/test_zoneinfo.py or test/test_zoneinfo/__init__.py because we may do some refactoring in the future that would likely require this separation anyway; we may: - include the property tests - automatically run all the tests against both pure Python and C, rather than manually constructing C and Python test classes (similar to the way this works with test_datetime.py, which generates C and Python test cases from datetimetester.py). - This includes a compile-time configuration option on Linux (though not on Windows); added with much help from Thomas Wouters. - Integration into the CPython build system is obviously different from building a standalone zoneinfo module wheel. - This includes configuration to install the tzdata package as part of CI, though only on the coverage jobs. Introducing a PyPI dependency as part of the CI build was controversial, and this is seen as less of a major change, since the coverage jobs already depend on pip and PyPI. Additional changes that were introduced as part of this PR, most / all of which were backported to the reference implementation: - Fixed reference and memory leaks With much debugging help from Pablo Galindo - Added smoke tests ensuring that the C and Python modules are built The import machinery can be somewhat fragile, and the "seamlessly falls back to pure Python" nature of this module makes it so that a problem building the C extension or a failure to import the pure Python version might easily go unnoticed. - Adjustments to zoneinfo.__dir__ Suggested by Petr Viktorin. - Slight refactorings as suggested by Steve Dower. - Removed unnecessary if check on std_abbr Discovered this because of a missing line in branch coverage.
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OS_ENV_LOCK = threading.Lock()
TZPATH_LOCK = threading.Lock()
TZPATH_TEST_LOCK = threading.Lock()
def call_once(f):
"""Decorator that ensures a function is only ever called once."""
lock = threading.Lock()
cached = functools.lru_cache(None)(f)
@functools.wraps(f)
def inner():
with lock:
return cached()
return inner
@call_once
def get_modules():
"""Retrieve two copies of zoneinfo: pure Python and C accelerated.
Because this function manipulates the import system in a way that might
be fragile or do unexpected things if it is run many times, it uses a
`call_once` decorator to ensure that this is only ever called exactly
one time in other words, when using this function you will only ever
get one copy of each module rather than a fresh import each time.
"""
import zoneinfo as c_module
py_module = import_fresh_module("zoneinfo", blocked=["_zoneinfo"])
return py_module, c_module
@contextlib.contextmanager
def set_zoneinfo_module(module):
"""Make sure sys.modules["zoneinfo"] refers to `module`.
This is necessary because `pickle` will refuse to serialize
an type calling itself `zoneinfo.ZoneInfo` unless `zoneinfo.ZoneInfo`
refers to the same object.
"""
NOT_PRESENT = object()
old_zoneinfo = sys.modules.get("zoneinfo", NOT_PRESENT)
sys.modules["zoneinfo"] = module
yield
if old_zoneinfo is not NOT_PRESENT:
sys.modules["zoneinfo"] = old_zoneinfo
else: # pragma: nocover
sys.modules.pop("zoneinfo")
class ZoneInfoTestBase(unittest.TestCase):
@classmethod
def setUpClass(cls):
cls.klass = cls.module.ZoneInfo
super().setUpClass()
@contextlib.contextmanager
def tzpath_context(self, tzpath, block_tzdata=True, lock=TZPATH_LOCK):
def pop_tzdata_modules():
tzdata_modules = {}
for modname in list(sys.modules):
if modname.split(".", 1)[0] != "tzdata": # pragma: nocover
continue
tzdata_modules[modname] = sys.modules.pop(modname)
return tzdata_modules
bpo-40503: PEP 615: Tests and implementation for zoneinfo (GH-19909) This is the initial implementation of PEP 615, the zoneinfo module, ported from the standalone reference implementation (see https://www.python.org/dev/peps/pep-0615/#reference-implementation for a link, which has a more detailed commit history). This includes (hopefully) all functional elements described in the PEP, but documentation is found in a separate PR. This includes: 1. A pure python implementation of the ZoneInfo class 2. A C accelerated implementation of the ZoneInfo class 3. Tests with 100% branch coverage for the Python code (though C code coverage is less than 100%). 4. A compile-time configuration option on Linux (though not on Windows) Differences from the reference implementation: - The module is arranged slightly differently: the accelerated module is `_zoneinfo` rather than `zoneinfo._czoneinfo`, which also necessitates some changes in the test support function. (Suggested by Victor Stinner and Steve Dower.) - The tests are arranged slightly differently and do not include the property tests. The tests live at test/test_zoneinfo/test_zoneinfo.py rather than test/test_zoneinfo.py or test/test_zoneinfo/__init__.py because we may do some refactoring in the future that would likely require this separation anyway; we may: - include the property tests - automatically run all the tests against both pure Python and C, rather than manually constructing C and Python test classes (similar to the way this works with test_datetime.py, which generates C and Python test cases from datetimetester.py). - This includes a compile-time configuration option on Linux (though not on Windows); added with much help from Thomas Wouters. - Integration into the CPython build system is obviously different from building a standalone zoneinfo module wheel. - This includes configuration to install the tzdata package as part of CI, though only on the coverage jobs. Introducing a PyPI dependency as part of the CI build was controversial, and this is seen as less of a major change, since the coverage jobs already depend on pip and PyPI. Additional changes that were introduced as part of this PR, most / all of which were backported to the reference implementation: - Fixed reference and memory leaks With much debugging help from Pablo Galindo - Added smoke tests ensuring that the C and Python modules are built The import machinery can be somewhat fragile, and the "seamlessly falls back to pure Python" nature of this module makes it so that a problem building the C extension or a failure to import the pure Python version might easily go unnoticed. - Adjustments to zoneinfo.__dir__ Suggested by Petr Viktorin. - Slight refactorings as suggested by Steve Dower. - Removed unnecessary if check on std_abbr Discovered this because of a missing line in branch coverage.
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with lock:
if block_tzdata:
# In order to fully exclude tzdata from the path, we need to
# clear the sys.modules cache of all its contents — setting the
# root package to None is not enough to block direct access of
# already-imported submodules (though it will prevent new
# imports of submodules).
tzdata_modules = pop_tzdata_modules()
sys.modules["tzdata"] = None
bpo-40503: PEP 615: Tests and implementation for zoneinfo (GH-19909) This is the initial implementation of PEP 615, the zoneinfo module, ported from the standalone reference implementation (see https://www.python.org/dev/peps/pep-0615/#reference-implementation for a link, which has a more detailed commit history). This includes (hopefully) all functional elements described in the PEP, but documentation is found in a separate PR. This includes: 1. A pure python implementation of the ZoneInfo class 2. A C accelerated implementation of the ZoneInfo class 3. Tests with 100% branch coverage for the Python code (though C code coverage is less than 100%). 4. A compile-time configuration option on Linux (though not on Windows) Differences from the reference implementation: - The module is arranged slightly differently: the accelerated module is `_zoneinfo` rather than `zoneinfo._czoneinfo`, which also necessitates some changes in the test support function. (Suggested by Victor Stinner and Steve Dower.) - The tests are arranged slightly differently and do not include the property tests. The tests live at test/test_zoneinfo/test_zoneinfo.py rather than test/test_zoneinfo.py or test/test_zoneinfo/__init__.py because we may do some refactoring in the future that would likely require this separation anyway; we may: - include the property tests - automatically run all the tests against both pure Python and C, rather than manually constructing C and Python test classes (similar to the way this works with test_datetime.py, which generates C and Python test cases from datetimetester.py). - This includes a compile-time configuration option on Linux (though not on Windows); added with much help from Thomas Wouters. - Integration into the CPython build system is obviously different from building a standalone zoneinfo module wheel. - This includes configuration to install the tzdata package as part of CI, though only on the coverage jobs. Introducing a PyPI dependency as part of the CI build was controversial, and this is seen as less of a major change, since the coverage jobs already depend on pip and PyPI. Additional changes that were introduced as part of this PR, most / all of which were backported to the reference implementation: - Fixed reference and memory leaks With much debugging help from Pablo Galindo - Added smoke tests ensuring that the C and Python modules are built The import machinery can be somewhat fragile, and the "seamlessly falls back to pure Python" nature of this module makes it so that a problem building the C extension or a failure to import the pure Python version might easily go unnoticed. - Adjustments to zoneinfo.__dir__ Suggested by Petr Viktorin. - Slight refactorings as suggested by Steve Dower. - Removed unnecessary if check on std_abbr Discovered this because of a missing line in branch coverage.
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old_path = self.module.TZPATH
try:
self.module.reset_tzpath(tzpath)
yield
finally:
if block_tzdata:
sys.modules.pop("tzdata")
for modname, module in tzdata_modules.items():
sys.modules[modname] = module
bpo-40503: PEP 615: Tests and implementation for zoneinfo (GH-19909) This is the initial implementation of PEP 615, the zoneinfo module, ported from the standalone reference implementation (see https://www.python.org/dev/peps/pep-0615/#reference-implementation for a link, which has a more detailed commit history). This includes (hopefully) all functional elements described in the PEP, but documentation is found in a separate PR. This includes: 1. A pure python implementation of the ZoneInfo class 2. A C accelerated implementation of the ZoneInfo class 3. Tests with 100% branch coverage for the Python code (though C code coverage is less than 100%). 4. A compile-time configuration option on Linux (though not on Windows) Differences from the reference implementation: - The module is arranged slightly differently: the accelerated module is `_zoneinfo` rather than `zoneinfo._czoneinfo`, which also necessitates some changes in the test support function. (Suggested by Victor Stinner and Steve Dower.) - The tests are arranged slightly differently and do not include the property tests. The tests live at test/test_zoneinfo/test_zoneinfo.py rather than test/test_zoneinfo.py or test/test_zoneinfo/__init__.py because we may do some refactoring in the future that would likely require this separation anyway; we may: - include the property tests - automatically run all the tests against both pure Python and C, rather than manually constructing C and Python test classes (similar to the way this works with test_datetime.py, which generates C and Python test cases from datetimetester.py). - This includes a compile-time configuration option on Linux (though not on Windows); added with much help from Thomas Wouters. - Integration into the CPython build system is obviously different from building a standalone zoneinfo module wheel. - This includes configuration to install the tzdata package as part of CI, though only on the coverage jobs. Introducing a PyPI dependency as part of the CI build was controversial, and this is seen as less of a major change, since the coverage jobs already depend on pip and PyPI. Additional changes that were introduced as part of this PR, most / all of which were backported to the reference implementation: - Fixed reference and memory leaks With much debugging help from Pablo Galindo - Added smoke tests ensuring that the C and Python modules are built The import machinery can be somewhat fragile, and the "seamlessly falls back to pure Python" nature of this module makes it so that a problem building the C extension or a failure to import the pure Python version might easily go unnoticed. - Adjustments to zoneinfo.__dir__ Suggested by Petr Viktorin. - Slight refactorings as suggested by Steve Dower. - Removed unnecessary if check on std_abbr Discovered this because of a missing line in branch coverage.
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self.module.reset_tzpath(old_path)