If you are just looking to test the whole code and not worry about the actual pins (as windows machines don't have GPIO), then you can fake it. First, in your main python source directory, create a directory named "RPi". In that folder, put an empty text file named __init__.py. This lets python know the folder "RPi" is a package. Also in that folder put a text file named "GPIO.py". In that file put the following:

BOARD = 1
OUT = 1
IN = 1

def setmode(a):
   print a
def setup(a, b):
   print a
def output(a, b):
   print a
def cleanup():
   print 'a'
def setwarnings(flag):
   print 'False'

This puts a pretty blank attribute set that can answer some of the GPIO calls you would most likely be using. Of course, there is no way to actually check whether the calls worked, but you won't get error messages stating the module GPIO doesn't exist. It's pretty hacky, but I use it when I don't feel like ssh into my pi for some quick code updates. You can add any other GPIO attributes you may need.