Mocky 0.1

Mocky is a class that helps you create mock objects for use in doctests.

class Mocky(object):
"""Mocky is a class that wants to help you with setting up mock
objects for your tests. It helps you observe which functions get
called (with which parameters) and which attributes are set.

Unless given a name, a Mocky's name is 'root':

>>> Mocky().name
'root'

Let's start with a simple example that sets some variables so we
get a feeling of how Mocky works. Note that attribute accesss
will never result in AttributeError. Instead, an attribute access
to a nonexistent member variable will yield another Mocky
instance:

>>> f = Mocky('f')
>>> f
f
>>> unusual = f.unusual
>>> unusual
f.unusual
>>> type(unusual) is Mocky
True
>>> unusual is f.unusual
True
>>> f.a.c.r = 'Fidelio'
Set f.a.c.r to 'Fidelio'
>>> f.a.c.r
'Fidelio'

Note that when we set 'f.a.c.r' to 'Fidelio', Mocky printed out
that the attribute was set. Suppose we have a function 'fun' that
sets some fancy variable on a given object:

>>> def fun(obj):
... if obj.please_process_me:
... obj.there_you = 'go'
>>> myobj = Mocky('myobj')
>>> fun(myobj)
Set myobj.there_you to 'go'
>>> myobj.please_process_me = False
Set myobj.please_process_me to False
>>> fun(myobj)

Mocky also supports calling. Another function that does a bit
more with our test object:

>>> def starve(character):
... character.getStatus().hitpoints -= 1
>>> starve(Mocky('Hugo')) # doctest: +ELLIPSIS
Traceback (most recent call last):
...
TypeError: unsupported operand type(s) for -=: 'Mocky' and 'int'
>>> ezequiel = Mocky('ezequiel')
>>> ezequiel.getStatus().hitpoints = 0
Called ezequiel.getStatus()
Set ezequiel.getStatus().hitpoints to 0
>>> starve(ezequiel)
Called ezequiel.getStatus()
Set ezequiel.getStatus().hitpoints to -1

For calls, Mocky will return the same value if the signature is
the same:

>>> secret = f.unusual(password='secret')
Called f.unusual(password='secret')
>>> secret is f.unusual(password='secret')
Called f.unusual(password='secret')
True
>>> secret is f.unusual(password='unsafe')
Called f.unusual(password='unsafe')
False
"""
def __init__(self, name='root'):
self.__dict__['name'] = name
self.__dict__['_calls'] = {}

def __call__(self, *args, **kwargs):
argsstr = ', '.join([repr(arg) for arg in args])
keys = sorted(kwargs.keys())
kwargsstr = ', '.join(['%s=%r' % (key, kwargs[key]) for key in keys])
if argsstr and kwargsstr:
allargs = ', '.join([argsstr, kwargsstr])
else:
allargs = argsstr or kwargsstr

print "Called %s(%s)" % (self.name, allargs)
if allargs not in self._calls:
self._calls[allargs] = Mocky('%s(%s)' % (self.name, allargs))
return self._calls[allargs]

def __repr__(self):
return self.name

def __getattr__(self, name):
if name not in self.__dict__:
self.__dict__[name] = Mocky('%s.%s' % (self.name, name))
return self.__dict__[name]

def __setattr__(self, name, value):
print "Set %s.%s to %r" % (self.name, name, value)
self.__dict__[name] = value