- Stuff
- 2007 year 2 month 25 day Sunday 11:16:44 MDT
- """
- Mock object implementation.
- This mock object implementation is meant to be very forgiving - it returns a
- new child Mock Object for every attribute accessed, and a mock object is
- returned from every method call.
- It is the tester's job to enabled the calls that they are interested in
- testing, all calls where the return value of the call and side effects are not
- recorded (logging, for example) are likely to succeed w/o effort.
- If you wish to call the actual implementation of a function on a MockObject,
- you have to enable it using enableMethod. If you wish to use an actual variable setting, you need to set it.
- All enabling/checking methods for a MockObject are done through the _mock attribute. Example:
- class Foo(object):
- def __init__(self):
- # NOTE: this initialization is not called by default with the mock
- # object.
- self.one = 'a'
- self.two = 'b'
- def method(self, param):
- # this method is enabled by calling _mock.enableMethod
- param.bar('print some data')
- self.printMe('some other data', self.one)
- return self.two
- def printMe(self, otherParam):
- # this method is not enabled and so is stubbed out in the MockInstance.
- print otherParam
- def test():
- m = MockInstance(Foo)
- m._mock.set(two=123)
- m._mock.enableMethod('method')
- param = MockObject()
- rv = m.method(param)
- assert(rv == 123) #m.two is returned
- # note that param.bar is created on the fly as it is accessed, and
- # stores how it was called.
- assert(param.bar._mock.assertCalled('print some data')
- # m.one and m.printMe were created on the fly as well
- # m.printMe remembers how it was called.
- m.printMe._mock.assertCalled('some other data', m.one)
- # attribute values are generated on the fly but are retained between
- # accesses.
- assert(m.foo is m.foo)
- TODO: set the return values for particular function calls w/ particular
- parameters.
- """
- import new
- class MockObject(object):
- """
- Base mock object.
- Creates attributes on the fly, affect attribute values by using
- the _mock attribute, which is a MockManager.
- Initial attributes can be assigned by key/value pairs passed in.
- """
- def __init__(self, **kw):
- self._mock = MockManager(self)
- self.__dict__.update(kw)
- self._mock._dict = {}
- def __getattribute__(self, key):
- if key == '_mock' or self._mock.enabled(key):
- return object.__getattribute__(self, key)
- if key in self.__dict__:
- return self.__dict__[key]
- m = self._mock.getCalled(key)
- self.__dict__[key] = m
- return m
- def __setattr__(self, key, value):
- if key == '_mock' or self._mock.enabled(key):
- object.__setattr__(self, key, value)
- else:
- m = self._mock.setCalled(key, value)
- if not hasattr(self, key):
- object.__setattr__(self, key, m)
- def __setitem__(self, key, value):
- m = self._mock.setItemCalled(key, value)
- self._mock._dict[key] = m
- def __len__(self):
- return self._mock.length
- def __iter__(self):
- for i in range(len(self)):
- yield self[i]
- def __getitem__(self, key):
- if key in self._mock._dict:
- return self._mock._dict[key]
- else:
- m = self._mock.getItemCalled(key)
- self._mock._dict[key] = m
- return m
- def __hasattr__(self, key):
- if key == '_mock' or self._mock.enabled(key):
- return object.__hasattr__(self, key)
- return True
- def __call__(self, *args, **kw):
- return self._mock.called(args, kw)
- class MockManager(object):
- def __init__(self, obj):
- self._enabledByDefault = False
- self._enabled = set(['__dict__', '__methods__', '__class__',
- '__members__'])
- self._disabled = set([])
- self._errorToRaise = None
- self.calls = []
- self.callReturns = []
- self.getCalls = []
- self.setCalls = []
- self.getItemCalls = []
- self.setItemCalls = []
- self.hasCalls = []
- self.eqCalls = []
- self.obj = obj
- self.superClass = object
- self.length = 1
- def enableByDefault(self):
- self._enabledByDefault = True
- def disableByDefault(self):
- self._enabledByDefault = False
- def setReturn(self, returnValue, *args, **kw):
- self.callReturns.append((args, tuple(sorted(kw.items())), returnValue))
- def enableMethod(self, name):
- """
- Enables a method to be called from the given superclass.
- The function underlying the method is slurped up and assigned to
- this class.
- """
- self.enable(name)
- func = getattr(self.superClass, name).im_func
- method = new.instancemethod(func, self.obj, self.obj.__class__)
- object.__setattr__(self.obj, name, method)
- def enable(self, *names):
- self._enabled.update(names)
- self._disabled.difference_update(names)
- def disable(self, *names):
- self._enabled.difference_update(names)
- self._disabled.update(names)
- for name in names:
- object.__setattr__(self.obj, name, MockObject())
- def enabled(self, name):
- if self._enabledByDefault:
- return name not in self._disabled
- else:
- return name in self._enabled
- def set(self, **kw):
- for key, value in kw.iteritems():
- self._enabled.add(key)
- setattr(self.obj, key, value)
- def raiseErrorOnAccess(self, error):
- self._errorToRaise = error
- def assertCalled(self, *args, **kw):
- kw = tuple(sorted(kw.items()))
- assert((args, kw) in self.calls)
- self.calls.remove((args, kw))
- def assertNotCalled(self, *args, **kw):
- assert(not self.calls)
- def setCalled(self, key, value):
- if self._errorToRaise:
- self._raiseError()
- m = MockObject()
- self.setCalls.append((key, value, m))
- return m
- def setItemCalled(self, key, value):
- if self._errorToRaise:
- self._raiseError()
- m = MockObject()
- self.setItemCalls.append((key, value, m))
- return m
- def _raiseError(self):
- err = self._errorToRaise
- self._errorToRaise = None
- raise err
- def getCalled(self, key):
- if self._errorToRaise:
- self._raiseError()
- m = MockObject()
- self.getCalls.append((key, m))
- return m
- def getItemCalled(self, key):
- if self._errorToRaise:
- self._raiseError()
- m = MockObject()
- self.getItemCalls.append((key, m))
- return m
- def called(self, args, kw):
- kw = tuple(sorted(kw.items()))
- self.calls.append((args, kw))
- if self._errorToRaise:
- self._raiseError()
- else:
- rv = [x[2] for x in self.callReturns if (x[0], x[1]) == (args, kw)]
- if rv:
- return rv[-1]
- else:
- return MockObject()
- def getCalls(self):
- return self.calls
- def popCall(self):
- call = self.calls[0]
- self.calls = self.calls[1:]
- return call
- class MockInstance(MockObject):
- def __init__(self, superClass, **kw):
- MockObject.__init__(self, **kw)
- self._mock.superClass = superClass
- def attach(obj):
- if hasattr(obj, '__setattr__'):
- oldsetattr = obj.__setattr__
- if hasattr(obj, '__getattribute__'):
- oldgetattr = obj.__getattribute__
- def __setattr__(self, key, value):
- if not isinstance(getattr(self, key), mock.MockObject()):
- oldsetattr(key, value)
- def __getattribute__(self, key):
- if not hasattr(self, key):
- oldsetattr(key, mock.MockObject())
- return oldgetattr(key)
- oldsetattr('__setattr__', new.instancemethod(__setattr__, obj,
- obj.__class__))
- oldsetattr('__getattribute__', new.instancemethod(__getattribute__, obj, obj.__class__))
- def mockMethod(method):
- self = method.im_self
- name = method.__name__
- origMethod = getattr(self, name)
- setattr(self, name, MockObject())
- getattr(self, name)._mock.method = origMethod
- getattr(self, name)._mock.origValue = origMethod
- def mock(obj, attr):
- m = MockObject()
- if hasattr(obj, attr):
- m._mock.origValue = getattr(obj, attr)
- setattr(obj, attr, m)
- def mockClass(class_, *args, **kw):
- commands = []
- runInit = kw.pop('mock_runInit', False)
- for k, v in kw.items():
- if k.startswith('mock_'):
- if not isinstance(v, (list, tuple)):
- v = [v]
- commands.append((k[5:], v))
- kw.pop(k)
- class _MockClass(MockInstance, class_):
- def __init__(self, *a, **k):
- MockInstance.__init__(self, class_, *args, **kw)
- if runInit:
- self._mock.enableByDefault()
- class_.__init__(self, *a, **k)
- self._mock.called(a, k)
- for command, params in commands:
- getattr(self._mock, command)(*params)
- return _MockClass
- def mockFunctionOnce(obj, attr, returnValue):
- newFn = lambda *args, **kw: returnValue
- return replaceFunctionOnce(obj, attr, newFn)
- def replaceFunctionOnce(obj, attr, newFn):
- curValue = getattr(obj, attr)
- def restore():
- setattr(obj, attr, curValue)
- def fun(*args, **kw):
- restore()
- return newFn(*args, **kw)
- setattr(obj, attr, fun)
- fun.func_name = attr
- fun.restore = restore
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