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move python api helpers out of the python module
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this separates exposed normal api from collection elements
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@RonnyPfannschmidt
RonnyPfannschmidt committed Jun 11, 2017
1 parent 36251e0 commit 6be57a3
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174 changes: 0 additions & 174 deletions _pytest/python.py
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,6 @@
import sys
import os
import collections
import math
from itertools import count

import py
Expand Down Expand Up @@ -1091,179 +1090,6 @@ def _showfixtures_main(config, session):
red=True)


# builtin pytest.raises helper

def raises(expected_exception, *args, **kwargs):
"""
Assert that a code block/function call raises ``expected_exception``
and raise a failure exception otherwise.
This helper produces a ``ExceptionInfo()`` object (see below).
If using Python 2.5 or above, you may use this function as a
context manager::
>>> with raises(ZeroDivisionError):
... 1/0
.. versionchanged:: 2.10
In the context manager form you may use the keyword argument
``message`` to specify a custom failure message::
>>> with raises(ZeroDivisionError, message="Expecting ZeroDivisionError"):
... pass
Traceback (most recent call last):
...
Failed: Expecting ZeroDivisionError
.. note::
When using ``pytest.raises`` as a context manager, it's worthwhile to
note that normal context manager rules apply and that the exception
raised *must* be the final line in the scope of the context manager.
Lines of code after that, within the scope of the context manager will
not be executed. For example::
>>> value = 15
>>> with raises(ValueError) as exc_info:
... if value > 10:
... raise ValueError("value must be <= 10")
... assert exc_info.type == ValueError # this will not execute
Instead, the following approach must be taken (note the difference in
scope)::
>>> with raises(ValueError) as exc_info:
... if value > 10:
... raise ValueError("value must be <= 10")
...
>>> assert exc_info.type == ValueError
Or you can use the keyword argument ``match`` to assert that the
exception matches a text or regex::
>>> with raises(ValueError, match='must be 0 or None'):
... raise ValueError("value must be 0 or None")
>>> with raises(ValueError, match=r'must be \d+$'):
... raise ValueError("value must be 42")
Or you can specify a callable by passing a to-be-called lambda::
>>> raises(ZeroDivisionError, lambda: 1/0)
<ExceptionInfo ...>
or you can specify an arbitrary callable with arguments::
>>> def f(x): return 1/x
...
>>> raises(ZeroDivisionError, f, 0)
<ExceptionInfo ...>
>>> raises(ZeroDivisionError, f, x=0)
<ExceptionInfo ...>
A third possibility is to use a string to be executed::
>>> raises(ZeroDivisionError, "f(0)")
<ExceptionInfo ...>
.. autoclass:: _pytest._code.ExceptionInfo
:members:
.. note::
Similar to caught exception objects in Python, explicitly clearing
local references to returned ``ExceptionInfo`` objects can
help the Python interpreter speed up its garbage collection.
Clearing those references breaks a reference cycle
(``ExceptionInfo`` --> caught exception --> frame stack raising
the exception --> current frame stack --> local variables -->
``ExceptionInfo``) which makes Python keep all objects referenced
from that cycle (including all local variables in the current
frame) alive until the next cyclic garbage collection run. See the
official Python ``try`` statement documentation for more detailed
information.
"""
__tracebackhide__ = True
msg = ("exceptions must be old-style classes or"
" derived from BaseException, not %s")
if isinstance(expected_exception, tuple):
for exc in expected_exception:
if not isclass(exc):
raise TypeError(msg % type(exc))
elif not isclass(expected_exception):
raise TypeError(msg % type(expected_exception))

message = "DID NOT RAISE {0}".format(expected_exception)
match_expr = None

if not args:
if "message" in kwargs:
message = kwargs.pop("message")
if "match" in kwargs:
match_expr = kwargs.pop("match")
message += " matching '{0}'".format(match_expr)
return RaisesContext(expected_exception, message, match_expr)
elif isinstance(args[0], str):
code, = args
assert isinstance(code, str)
frame = sys._getframe(1)
loc = frame.f_locals.copy()
loc.update(kwargs)
#print "raises frame scope: %r" % frame.f_locals
try:
code = _pytest._code.Source(code).compile()
py.builtin.exec_(code, frame.f_globals, loc)
# XXX didn'T mean f_globals == f_locals something special?
# this is destroyed here ...
except expected_exception:
return _pytest._code.ExceptionInfo()
else:
func = args[0]
try:
func(*args[1:], **kwargs)
except expected_exception:
return _pytest._code.ExceptionInfo()
fail(message)


raises.Exception = fail.Exception


class RaisesContext(object):
def __init__(self, expected_exception, message, match_expr):
self.expected_exception = expected_exception
self.message = message
self.match_expr = match_expr
self.excinfo = None

def __enter__(self):
self.excinfo = object.__new__(_pytest._code.ExceptionInfo)
return self.excinfo

def __exit__(self, *tp):
__tracebackhide__ = True
if tp[0] is None:
fail(self.message)
if sys.version_info < (2, 7):
# py26: on __exit__() exc_value often does not contain the
# exception value.
# http://bugs.python.org/issue7853
if not isinstance(tp[1], BaseException):
exc_type, value, traceback = tp
tp = exc_type, exc_type(value), traceback
self.excinfo.__init__(tp)
suppress_exception = issubclass(self.excinfo.type, self.expected_exception)
if sys.version_info[0] == 2 and suppress_exception:
sys.exc_clear()
if self.match_expr:
self.excinfo.match(self.match_expr)
return suppress_exception


#
# the basic pytest Function item
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