make something show up as a module to some supplied code you're going to exec

fakemoduletest.py

src = """
from fakemodule import fakefunc
fakefunc()
print dir()
"""

def call_with_fakemodule(usersrc):

    class fmod(object):
        @staticmethod
        def ffunc():
            print "called ffunc!"
        fakefunc = ffunc
    
    prefix = """
import sys
sys.modules['fakemodule'] = __tempcontext__
del __tempcontext__
del sys
"""
    
    exec (prefix + usersrc) in { '__tempcontext__' : fmod }

call_with_fakemodule(src)