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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
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Add m-esr52 at 52.6.0
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+""" monkeypatching and mocking functionality. """
+
+import os, sys
+import re
+
+from py.builtin import _basestring
+
+RE_IMPORT_ERROR_NAME = re.compile("^No module named (.*)$")
+
+
+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)
+ monkeypatch.chdir(path)
+
+ All modifications will be undone after the requesting
+ test function has finished. 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
+
+
+def resolve(name):
+ # simplified from zope.dottedname
+ parts = name.split('.')
+
+ used = parts.pop(0)
+ found = __import__(used)
+ for part in parts:
+ used += '.' + part
+ try:
+ found = getattr(found, part)
+ except AttributeError:
+ pass
+ else:
+ continue
+ # we use explicit un-nesting of the handling block in order
+ # to avoid nested exceptions on python 3
+ try:
+ __import__(used)
+ except ImportError as ex:
+ # str is used for py2 vs py3
+ expected = str(ex).split()[-1]
+ if expected == used:
+ raise
+ else:
+ raise ImportError(
+ 'import error in %s: %s' % (used, ex)
+ )
+ found = annotated_getattr(found, part, used)
+ return found
+
+
+def annotated_getattr(obj, name, ann):
+ try:
+ obj = getattr(obj, name)
+ except AttributeError:
+ raise AttributeError(
+ '%r object at %s has no attribute %r' % (
+ type(obj).__name__, ann, name
+ )
+ )
+ return obj
+
+
+def derive_importpath(import_path, raising):
+ if not isinstance(import_path, _basestring) or "." not in import_path:
+ raise TypeError("must be absolute import path string, not %r" %
+ (import_path,))
+ module, attr = import_path.rsplit('.', 1)
+ target = resolve(module)
+ if raising:
+ annotated_getattr(target, attr, ann=module)
+ return attr, target
+
+
+class Notset:
+ def __repr__(self):
+ return "<notset>"
+
+
+notset = Notset()
+
+
+class monkeypatch:
+ """ Object keeping a record of setattr/item/env/syspath changes. """
+
+ def __init__(self):
+ self._setattr = []
+ self._setitem = []
+ self._cwd = None
+ self._savesyspath = None
+
+ def setattr(self, target, name, value=notset, raising=True):
+ """ Set attribute value on target, memorizing the old value.
+ By default raise AttributeError if the attribute did not exist.
+
+ For convenience you can specify a string as ``target`` which
+ will be interpreted as a dotted import path, with the last part
+ being the attribute name. Example:
+ ``monkeypatch.setattr("os.getcwd", lambda x: "/")``
+ would set the ``getcwd`` function of the ``os`` module.
+
+ The ``raising`` value determines if the setattr should fail
+ if the attribute is not already present (defaults to True
+ which means it will raise).
+ """
+ __tracebackhide__ = True
+ import inspect
+
+ if value is notset:
+ if not isinstance(target, _basestring):
+ raise TypeError("use setattr(target, name, value) or "
+ "setattr(target, value) with target being a dotted "
+ "import string")
+ value = name
+ name, target = derive_importpath(target, raising)
+
+ oldval = getattr(target, name, notset)
+ if raising and oldval is notset:
+ raise AttributeError("%r has no attribute %r" % (target, name))
+
+ # avoid class descriptors like staticmethod/classmethod
+ if inspect.isclass(target):
+ oldval = target.__dict__.get(name, notset)
+ self._setattr.append((target, name, oldval))
+ setattr(target, name, value)
+
+ def delattr(self, target, name=notset, raising=True):
+ """ Delete attribute ``name`` from ``target``, by default raise
+ AttributeError it the attribute did not previously exist.
+
+ If no ``name`` is specified and ``target`` is a string
+ it will be interpreted as a dotted import path with the
+ last part being the attribute name.
+
+ If ``raising`` is set to False, no exception will be raised if the
+ attribute is missing.
+ """
+ __tracebackhide__ = True
+ if name is notset:
+ if not isinstance(target, _basestring):
+ raise TypeError("use delattr(target, name) or "
+ "delattr(target) with target being a dotted "
+ "import string")
+ name, target = derive_importpath(target, raising)
+
+ if not hasattr(target, name):
+ if raising:
+ raise AttributeError(name)
+ else:
+ self._setattr.append((target, name, getattr(target, name, notset)))
+ delattr(target, name)
+
+ def setitem(self, dic, name, value):
+ """ Set dictionary entry ``name`` to value. """
+ self._setitem.append((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 ``raising`` is set to False, no exception will be raised if the
+ key is missing.
+ """
+ if name not in dic:
+ if raising:
+ raise KeyError(name)
+ else:
+ self._setitem.append((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 the environment. Raise KeyError it does not
+ exist.
+
+ If ``raising`` is set to False, no exception will be raised if the
+ environment variable is missing.
+ """
+ self.delitem(os.environ, name, raising=raising)
+
+ def syspath_prepend(self, path):
+ """ Prepend ``path`` to ``sys.path`` list of import locations. """
+ if self._savesyspath is None:
+ self._savesyspath = sys.path[:]
+ sys.path.insert(0, str(path))
+
+ def chdir(self, path):
+ """ Change the current working directory to the specified path.
+ Path can be a string or a py.path.local object.
+ """
+ if self._cwd is None:
+ self._cwd = os.getcwd()
+ if hasattr(path, "chdir"):
+ path.chdir()
+ else:
+ os.chdir(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.
+
+ There is generally no need to call `undo()`, since it is
+ called automatically during tear-down.
+
+ Note that the same `monkeypatch` fixture is used across a
+ single test function invocation. If `monkeypatch` is used both by
+ the test function itself and one of the test fixtures,
+ calling `undo()` will undo all of the changes made in
+ both functions.
+ """
+ for obj, name, value in reversed(self._setattr):
+ if value is not notset:
+ setattr(obj, name, value)
+ else:
+ delattr(obj, name)
+ self._setattr[:] = []
+ for dictionary, name, value in reversed(self._setitem):
+ if value is notset:
+ try:
+ del dictionary[name]
+ except KeyError:
+ pass # was already deleted, so we have the desired state
+ else:
+ dictionary[name] = value
+ self._setitem[:] = []
+ if self._savesyspath is not None:
+ sys.path[:] = self._savesyspath
+ self._savesyspath = None
+
+ if self._cwd is not None:
+ os.chdir(self._cwd)
+ self._cwd = None