Viewing file:  assertions.py (5.04 KB) -rw-r--r--
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import contextlib
import re
import sys
def eq_(a, b, msg=None):
"""Assert a == b, with repr messaging on failure."""
assert a == b, msg or "%r != %r" % (a, b)
def ne_(a, b, msg=None):
"""Assert a != b, with repr messaging on failure."""
assert a != b, msg or "%r == %r" % (a, b)
def in_(a, b, msg=None):
"""Assert a in b, with repr messaging on failure."""
assert a in b, msg or "%r not in %r" % (a, b)
def not_in(a, b, msg=None):
"""Assert a in not b, with repr messaging on failure."""
assert a not in b, msg or "%r is in %r" % (a, b)
def _assert_proper_exception_context(exception):
"""assert that any exception we're catching does not have a __context__
without a __cause__, and that __suppress_context__ is never set.
Python 3 will report nested as exceptions as "during the handling of
error X, error Y occurred". That's not what we want to do. We want
these exceptions in a cause chain.
"""
if (
exception.__context__ is not exception.__cause__
and not exception.__suppress_context__
):
assert False, (
"Exception %r was correctly raised but did not set a cause, "
"within context %r as its cause."
% (exception, exception.__context__)
)
def _assert_proper_cause_cls(exception, cause_cls):
"""assert that any exception we're catching does not have a __context__
without a __cause__, and that __suppress_context__ is never set.
Python 3 will report nested as exceptions as "during the handling of
error X, error Y occurred". That's not what we want to do. We want
these exceptions in a cause chain.
"""
assert isinstance(exception.__cause__, cause_cls), (
"Exception %r was correctly raised but has cause %r, which does not "
"have the expected cause type %r."
% (exception, exception.__cause__, cause_cls)
)
def assert_raises(except_cls, callable_, *args, **kw):
return _assert_raises(except_cls, callable_, args, kw)
def assert_raises_with_proper_context(except_cls, callable_, *args, **kw):
return _assert_raises(except_cls, callable_, args, kw, check_context=True)
def assert_raises_with_given_cause(
except_cls, cause_cls, callable_, *args, **kw
):
return _assert_raises(except_cls, callable_, args, kw, cause_cls=cause_cls)
def assert_raises_message(except_cls, msg, callable_, *args, **kwargs):
return _assert_raises(except_cls, callable_, args, kwargs, msg=msg)
def assert_raises_message_with_proper_context(
except_cls, msg, callable_, *args, **kwargs
):
return _assert_raises(
except_cls, callable_, args, kwargs, msg=msg, check_context=True
)
def assert_raises_message_with_given_cause(
except_cls, msg, cause_cls, callable_, *args, **kwargs
):
return _assert_raises(
except_cls, callable_, args, kwargs, msg=msg, cause_cls=cause_cls
)
def _assert_raises(
except_cls,
callable_,
args,
kwargs,
msg=None,
check_context=False,
cause_cls=None,
):
with _expect_raises(except_cls, msg, check_context, cause_cls) as ec:
callable_(*args, **kwargs)
return ec.error
class _ErrorContainer:
error = None
@contextlib.contextmanager
def _expect_raises(except_cls, msg=None, check_context=False, cause_cls=None):
ec = _ErrorContainer()
if check_context:
are_we_already_in_a_traceback = sys.exc_info()[0]
try:
yield ec
success = False
except except_cls as err:
ec.error = err
success = True
if msg is not None:
# I'm often pdbing here, and "err" above isn't
# in scope, so assign the string explicitly
error_as_string = str(err)
assert re.search(msg, error_as_string, re.UNICODE), "%r !~ %s" % (
msg,
error_as_string,
)
if cause_cls is not None:
_assert_proper_cause_cls(err, cause_cls)
if check_context and not are_we_already_in_a_traceback:
_assert_proper_exception_context(err)
print(str(err).encode("utf-8"))
# it's generally a good idea to not carry traceback objects outside
# of the except: block, but in this case especially we seem to have
# hit some bug in either python 3.10.0b2 or greenlet or both which
# this seems to fix:
# https://github.com/python-greenlet/greenlet/issues/242
del ec
# assert outside the block so it works for AssertionError too !
assert success, "Callable did not raise an exception"
def expect_raises(except_cls, check_context=False):
return _expect_raises(except_cls, check_context=check_context)
def expect_raises_message(except_cls, msg, check_context=False):
return _expect_raises(except_cls, msg=msg, check_context=check_context)
def expect_raises_with_proper_context(except_cls, check_context=True):
return _expect_raises(except_cls, check_context=check_context)
def expect_raises_message_with_proper_context(
except_cls, msg, check_context=True
):
return _expect_raises(except_cls, msg=msg, check_context=check_context)
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