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forward port r66386

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This commit is contained in:
Benjamin Peterson 2008-10-16 23:24:44 +00:00
parent d31fdc547b
commit fcf5d639f5
9 changed files with 157 additions and 60 deletions
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40
Doc/library/test.rst
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@ -278,18 +278,26 @@ The :mod:`test.support` module defines the following functions:
This will run all tests defined in the named module.
.. function:: catch_warning(module=warnings, record=True)
.. function:: check_warnings()
Return a context manager that guards the warnings filter from being
permanently changed and optionally alters the :func:`showwarning`
function to record the details of any warnings that are issued in the
managed context. Attributes of the most recent warning are saved
directly on the context manager, while details of previous warnings
can be retrieved from the ``warnings`` list.
A convenience wrapper for ``warnings.catch_warnings()`` that makes
it easier to test that a warning was correctly raised with a single
assertion. It is approximately equivalent to calling
``warnings.catch_warnings(record=True)``.
The main difference is that on entry to the context manager, a
:class:`WarningRecorder` instance is returned instead of a simple list.
The underlying warnings list is available via the recorder object's
:attr:`warnings` attribute, while the attributes of the last raised
warning are also accessible directly on the object. If no warning has
been raised, then the latter attributes will all be :const:`None`.
A :meth:`reset` method is also provided on the recorder object. This
method simply clears the warning list.
The context manager is used like this::
with catch_warning() as w:
with check_warnings() as w:
warnings.simplefilter("always")
warnings.warn("foo")
assert str(w.message) == "foo"
@ -297,15 +305,9 @@ The :mod:`test.support` module defines the following functions:
assert str(w.message) == "bar"
assert str(w.warnings[0].message) == "foo"
assert str(w.warnings[1].message) == "bar"
w.reset()
assert len(w.warnings) == 0
By default, the real :mod:`warnings` module is affected - the ability
to select a different module is provided for the benefit of the
:mod:`warnings` module's own unit tests.
The ``record`` argument specifies whether or not the :func:`showwarning`
function is replaced. Note that recording the warnings in this fashion
also prevents them from being written to sys.stderr. If set to ``False``,
the standard handling of warning messages is left in place (however, the
original handling is still restored at the end of the block).
.. function:: captured_stdout()
@ -346,4 +348,10 @@ The :mod:`test.support` module defines the following classes:
Temporarily unset the environment variable ``envvar``.
.. class:: WarningsRecorder()
Class used to record warnings for unit tests. See documentation of
:func:`check_warnings` above for more details.
.. versionadded:: 2.6

34
Doc/library/warnings.rst
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@ -165,9 +165,9 @@ ImportWarning can also be enabled explicitly in Python code using::
Temporarily Suppressing Warnings
--------------------------------
If you are using code that you know will raise a warning, such some deprecated
function, but do not want to see the warning, then suppress the warning using
the :class:`catch_warnings` context manager::
If you are using code that you know will raise a warning, such as a deprecated
function, but do not want to see the warning, then it is possible to suppress
the warning using the :class:`catch_warnings` context manager::
import warnings
@ -218,7 +218,15 @@ the warning has been cleared.
Once the context manager exits, the warnings filter is restored to its state
when the context was entered. This prevents tests from changing the warnings
filter in unexpected ways between tests and leading to indeterminate test
results.
results. The :func:`showwarning` function in the module is also restored to
its original value.
When testing multiple operations that raise the same kind of warning, it
is important to test them in a manner that confirms each operation is raising
a new warning (e.g. set warnings to be raised as exceptions and check the
operations raise exceptions, check that the length of the warning list
continues to increase after each operation, or else delete the previous
entries from the warnings list before each new operation).
.. _warning-functions:
@ -314,20 +322,20 @@ Available Context Managers
.. class:: catch_warnings([\*, record=False, module=None])
A context manager that copies and, upon exit, restores the warnings filter.
If the *record* argument is False (the default) the context manager returns
:class:`None`. If *record* is true, a list is returned that is populated
with objects as seen by a custom :func:`showwarning` function (which also
suppresses output to ``sys.stdout``). Each object has attributes with the
same names as the arguments to :func:`showwarning`.
A context manager that copies and, upon exit, restores the warnings filter
and the :func:`showwarning` function.
If the *record* argument is :const:`False` (the default) the context manager
returns :class:`None` on entry. If *record* is :const:`True`, a list is
returned that is progressively populated with objects as seen by a custom
:func:`showwarning` function (which also suppresses output to ``sys.stdout``).
Each object in the list has attributes with the same names as the arguments to
:func:`showwarning`.
The *module* argument takes a module that will be used instead of the
module returned when you import :mod:`warnings` whose filter will be
protected. This arguments exists primarily for testing the :mod:`warnings`
protected. This argument exists primarily for testing the :mod:`warnings`
module itself.
.. versionadded:: 2.6
.. versionchanged:: 3.0
Constructor arguments turned into keyword-only arguments.

34
Lib/test/support.py
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@ -19,7 +19,7 @@ __all__ = ["Error", "TestFailed", "TestSkipped", "ResourceDenied", "import_modul
"is_resource_enabled", "requires", "find_unused_port", "bind_port",
"fcmp", "is_jython", "TESTFN", "HOST", "FUZZ", "findfile", "verify",
"vereq", "sortdict", "check_syntax_error", "open_urlresource",
"catch_warning", "CleanImport", "EnvironmentVarGuard",
"check_warnings", "CleanImport", "EnvironmentVarGuard",
"TransientResource", "captured_output", "captured_stdout",
"TransientResource", "transient_internet", "run_with_locale",
"set_memlimit", "bigmemtest", "bigaddrspacetest", "BasicTestRunner",
@ -53,7 +53,7 @@ class ResourceDenied(TestSkipped):
def import_module(name, deprecated=False):
"""Import the module to be tested, raising TestSkipped if it is not
available."""
with catch_warning(record=False):
with warnings.catch_warnings():
if deprecated:
warnings.filterwarnings("ignore", ".+ (module|package)",
DeprecationWarning)
@ -368,17 +368,27 @@ def open_urlresource(url, *args, **kw):
return open(fn, *args, **kw)
def catch_warning(module=warnings, record=True):
"""Guard the warnings filter from being permanently changed and
optionally record the details of any warnings that are issued.
Use like this:
with catch_warning() as w:
warnings.warn("foo")
assert str(w.message) == "foo"
class WarningsRecorder(object):
"""Convenience wrapper for the warnings list returned on
entry to the warnings.catch_warnings() context manager.
"""
return warnings.catch_warnings(record=record, module=module)
def __init__(self, warnings_list):
self.warnings = warnings_list
def __getattr__(self, attr):
if self.warnings:
return getattr(self.warnings[-1], attr)
elif attr in warnings.WarningMessage._WARNING_DETAILS:
return None
raise AttributeError("%r has no attribute %r" % (self, attr))
def reset(self):
del self.warnings[:]
@contextlib.contextmanager
def check_warnings():
with warnings.catch_warnings(record=True) as w:
yield WarningsRecorder(w)
class CleanImport(object):

13
Lib/test/test_import.py
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@ -266,21 +266,24 @@ class RelativeImport(unittest.TestCase):
self.assertTrue(hasattr(relimport, "RelativeImport"))
def test_issue3221(self):
# Note for mergers: the 'absolute' tests from the 2.x branch
# are missing in Py3k because implicit relative imports are
# a thing of the past
def check_relative():
exec("from . import relimport", ns)
# Check both OK with __package__ and __name__ correct
# Check relative import OK with __package__ and __name__ correct
ns = dict(__package__='test', __name__='test.notarealmodule')
check_relative()
# Check both OK with only __name__ wrong
# Check relative import OK with only __name__ wrong
ns = dict(__package__='test', __name__='notarealpkg.notarealmodule')
check_relative()
# Check relative fails with only __package__ wrong
# Check relative import fails with only __package__ wrong
ns = dict(__package__='foo', __name__='test.notarealmodule')
self.assertRaises(SystemError, check_relative)
# Check relative fails with __package__ and __name__ wrong
# Check relative import fails with __package__ and __name__ wrong
ns = dict(__package__='foo', __name__='notarealpkg.notarealmodule')
self.assertRaises(SystemError, check_relative)
# Check both fail with package set to a non-string
# Check relative import fails with package set to a non-string
ns = dict(__package__=object())
self.assertRaises(ValueError, check_relative)

14
Lib/test/test_structmembers.py
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@ -66,35 +66,35 @@ class ReadWriteTests(unittest.TestCase):
class TestWarnings(unittest.TestCase):
def has_warned(self, w):
self.assertEqual(w[-1].category, RuntimeWarning)
self.assertEqual(w.category, RuntimeWarning)
def test_byte_max(self):
with warnings.catch_warnings(record=True) as w:
with support.check_warnings() as w:
ts.T_BYTE = CHAR_MAX+1
self.has_warned(w)
def test_byte_min(self):
with warnings.catch_warnings(record=True) as w:
with support.check_warnings() as w:
ts.T_BYTE = CHAR_MIN-1
self.has_warned(w)
def test_ubyte_max(self):
with warnings.catch_warnings(record=True) as w:
with support.check_warnings() as w:
ts.T_UBYTE = UCHAR_MAX+1
self.has_warned(w)
def test_short_max(self):
with warnings.catch_warnings(record=True) as w:
with support.check_warnings() as w:
ts.T_SHORT = SHRT_MAX+1
self.has_warned(w)
def test_short_min(self):
with warnings.catch_warnings(record=True) as w:
with support.check_warnings() as w:
ts.T_SHORT = SHRT_MIN-1
self.has_warned(w)
def test_ushort_max(self):
with warnings.catch_warnings(record=True) as w:
with support.check_warnings() as w:
ts.T_USHORT = USHRT_MAX+1
self.has_warned(w)

2
Lib/test/test_sundry.py
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@ -7,7 +7,7 @@ import warnings
class TestUntestedModules(unittest.TestCase):
def test_at_least_import_untested_modules(self):
with warnings.catch_warnings(record=True):
with warnings.catch_warnings():
import aifc
import bdb
import cgitb

2
Lib/test/test_threading.py
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@ -1,7 +1,7 @@
# Very rudimentary test of threading module
import test.support
from test.support import verbose, catch_warning
from test.support import verbose
import random
import re
import sys

63
Lib/test/test_warnings.py
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@ -214,7 +214,8 @@ class WarnTests(unittest.TestCase):
def test_warn_nonstandard_types(self):
# warn() should handle non-standard types without issue.
for ob in (Warning, None, 42):
with support.catch_warning(self.module) as w:
with original_warnings.catch_warnings(record=True,
module=self.module) as w:
self.module.warn(ob)
# Don't directly compare objects since
# ``Warning() != Warning()``.
@ -526,19 +527,23 @@ class CatchWarningTests(BaseTest):
wmod = self.module
orig_filters = wmod.filters
orig_showwarning = wmod.showwarning
with support.catch_warning(module=wmod):
# Ensure both showwarning and filters are restored when recording
with wmod.catch_warnings(module=wmod, record=True):
wmod.filters = wmod.showwarning = object()
self.assert_(wmod.filters is orig_filters)
self.assert_(wmod.showwarning is orig_showwarning)
with support.catch_warning(module=wmod, record=False):
# Same test, but with recording disabled
with wmod.catch_warnings(module=wmod, record=False):
wmod.filters = wmod.showwarning = object()
self.assert_(wmod.filters is orig_filters)
self.assert_(wmod.showwarning is orig_showwarning)
def test_catch_warnings_recording(self):
wmod = self.module
with support.catch_warning(module=wmod) as w:
# Ensure warnings are recorded when requested
with wmod.catch_warnings(module=wmod, record=True) as w:
self.assertEqual(w, [])
self.assert_(type(w) is list)
wmod.simplefilter("always")
wmod.warn("foo")
self.assertEqual(str(w[-1].message), "foo")
@ -548,11 +553,59 @@ class CatchWarningTests(BaseTest):
self.assertEqual(str(w[1].message), "bar")
del w[:]
self.assertEqual(w, [])
# Ensure warnings are not recorded when not requested
orig_showwarning = wmod.showwarning
with support.catch_warning(module=wmod, record=False) as w:
with wmod.catch_warnings(module=wmod, record=False) as w:
self.assert_(w is None)
self.assert_(wmod.showwarning is orig_showwarning)
def test_catch_warnings_reentry_guard(self):
wmod = self.module
# Ensure catch_warnings is protected against incorrect usage
x = wmod.catch_warnings(module=wmod, record=True)
self.assertRaises(RuntimeError, x.__exit__)
with x:
self.assertRaises(RuntimeError, x.__enter__)
# Same test, but with recording disabled
x = wmod.catch_warnings(module=wmod, record=False)
self.assertRaises(RuntimeError, x.__exit__)
with x:
self.assertRaises(RuntimeError, x.__enter__)
def test_catch_warnings_defaults(self):
wmod = self.module
orig_filters = wmod.filters
orig_showwarning = wmod.showwarning
# Ensure default behaviour is not to record warnings
with wmod.catch_warnings(module=wmod) as w:
self.assert_(w is None)
self.assert_(wmod.showwarning is orig_showwarning)
self.assert_(wmod.filters is not orig_filters)
self.assert_(wmod.filters is orig_filters)
if wmod is sys.modules['warnings']:
# Ensure the default module is this one
with wmod.catch_warnings() as w:
self.assert_(w is None)
self.assert_(wmod.showwarning is orig_showwarning)
self.assert_(wmod.filters is not orig_filters)
self.assert_(wmod.filters is orig_filters)
def test_check_warnings(self):
# Explicit tests for the test.support convenience wrapper
wmod = self.module
if wmod is sys.modules['warnings']:
with support.check_warnings() as w:
self.assertEqual(w.warnings, [])
wmod.simplefilter("always")
wmod.warn("foo")
self.assertEqual(str(w.message), "foo")
wmod.warn("bar")
self.assertEqual(str(w.message), "bar")
self.assertEqual(str(w.warnings[0].message), "foo")
self.assertEqual(str(w.warnings[1].message), "bar")
w.reset()
self.assertEqual(w.warnings, [])
class CCatchWarningTests(CatchWarningTests):
module = c_warnings

15
Lib/warnings.py
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@ -301,8 +301,21 @@ class catch_warnings(object):
"""
self._record = record
self._module = sys.modules['warnings'] if module is None else module
self._entered = False
def __repr__(self):
args = []
if self._record:
args.append("record=True")
if self._module is not sys.modules['warnings']:
args.append("module=%r" % self._module)
name = type(self).__name__
return "%s(%s)" % (name, ", ".join(args))
def __enter__(self):
if self._entered:
raise RuntimeError("Cannot enter %r twice" % self)
self._entered = True
self._filters = self._module.filters
self._module.filters = self._filters[:]
self._showwarning = self._module.showwarning
@ -316,6 +329,8 @@ class catch_warnings(object):
return None
def __exit__(self, *exc_info):
if not self._entered:
raise RuntimeError("Cannot exit %r without entering first" % self)
self._module.filters = self._filters
self._module.showwarning = self._showwarning