How can I use monkey patching in Python to replace a specific argument?

Question

I want to use monkey patching to change all statements such as time.sleep(5) to myServer.sleep(5). How can I realize it? Thank you very much!

import test
import subprocess
import ast
import os
import time
import sys

if __name__ == "__main__":

    def insomniac(duration):
        pass  # don't sleep

    _original_sleep = time.sleep
    time.sleep = insomniac

    def dont_write(stuff):
        pass  # don't write

    _original_write = sys.stdout.write
    sys.stdout.write = dont_write

    execfile("test.py")

    exit(0)

Monkey-patching should not be your first resort. What goal are you trying to achieve by replacing these statements? — user2357112, Mar 14 '14 at 06:46
I want to test the original codes so don't want the time.sleep to waste time. — user3327884, Mar 14 '14 at 06:51

score 1 · Accepted Answer · edited May 23 '17 at 12:22

If your focus is on testing, i.e. you want to ensure that a callable in some external library out of your control is called in a specific way, there are testing libraries that can help you with this, such as mock. It can be pretty involving to set all those things up correctly so when I do coding I typically try to structure my code in a way that minimizes the usage of mocks.

Take a look at the documentation for mock if you really want to get your toes wet towards this direction. While at this, you probably should formalize your testing techniques to make use of unitttest. If you are lost, Writing unit tests in Python: How do I start?.

How can I use monkey patching in Python to replace a specific argument?

1 Answers1