test_ok1/_pytest/monkeypatch.py

104 lines
4.0 KiB
Python

""" monkeypatching and mocking functionality. """
import os, sys
def pytest_funcarg__monkeypatch(request):
"""The returned ``monkeypatch`` funcarg provides these
helper methods to modify objects, dictionaries or os.environ::
monkeypatch.setattr(obj, name, value, raising=True)
monkeypatch.delattr(obj, name, raising=True)
monkeypatch.setitem(mapping, name, value)
monkeypatch.delitem(obj, name, raising=True)
monkeypatch.setenv(name, value, prepend=False)
monkeypatch.delenv(name, value, raising=True)
monkeypatch.syspath_prepend(path)
All modifications will be undone when the requesting
test function finished its execution. The ``raising``
parameter determines if a KeyError or AttributeError
will be raised if the set/deletion operation has no target.
"""
mpatch = monkeypatch()
request.addfinalizer(mpatch.undo)
return mpatch
notset = object()
class monkeypatch:
""" object keeping a record of setattr/item/env/syspath changes. """
def __init__(self):
self._setattr = []
self._setitem = []
def setattr(self, obj, name, value, raising=True):
""" set attribute ``name`` on ``obj`` to ``value``, by default
raise AttributeEror if the attribute did not exist. """
oldval = getattr(obj, name, notset)
if raising and oldval is notset:
raise AttributeError("%r has no attribute %r" %(obj, name))
self._setattr.insert(0, (obj, name, oldval))
setattr(obj, name, value)
def delattr(self, obj, name, raising=True):
""" delete attribute ``name`` from ``obj``, by default raise
AttributeError it the attribute did not previously exist. """
if not hasattr(obj, name):
if raising:
raise AttributeError(name)
else:
self._setattr.insert(0, (obj, name, getattr(obj, name, notset)))
delattr(obj, name)
def setitem(self, dic, name, value):
""" set dictionary entry ``name`` to value. """
self._setitem.insert(0, (dic, name, dic.get(name, notset)))
dic[name] = value
def delitem(self, dic, name, raising=True):
""" delete ``name`` from dict, raise KeyError if it doesn't exist."""
if name not in dic:
if raising:
raise KeyError(name)
else:
self._setitem.insert(0, (dic, name, dic.get(name, notset)))
del dic[name]
def setenv(self, name, value, prepend=None):
""" set environment variable ``name`` to ``value``. if ``prepend``
is a character, read the current environment variable value
and prepend the ``value`` adjoined with the ``prepend`` character."""
value = str(value)
if prepend and name in os.environ:
value = value + prepend + os.environ[name]
self.setitem(os.environ, name, value)
def delenv(self, name, raising=True):
""" delete ``name`` from environment, raise KeyError it not exists."""
self.delitem(os.environ, name, raising=raising)
def syspath_prepend(self, path):
""" prepend ``path`` to ``sys.path`` list of import locations. """
if not hasattr(self, '_savesyspath'):
self._savesyspath = sys.path[:]
sys.path.insert(0, str(path))
def undo(self):
""" undo previous changes. This call consumes the
undo stack. Calling it a second time has no effect unless
you do more monkeypatching after the undo call."""
for obj, name, value in self._setattr:
if value is not notset:
setattr(obj, name, value)
else:
delattr(obj, name)
self._setattr[:] = []
for dictionary, name, value in self._setitem:
if value is notset:
del dictionary[name]
else:
dictionary[name] = value
self._setitem[:] = []
if hasattr(self, '_savesyspath'):
sys.path[:] = self._savesyspath