How to write a unittest that ignores a decorator

decorate.py

# let's say we have a function "testing" which is decorated by "my_decorator"
import functools

def my_decorator(func):
    @functools.wraps(func)
    def wrapped(*args, **kwargs):
        print("In real decorator")
        print(func.__name__)
        print(args)
        print(kwargs)
        return func(*args, **kwargs)

    # Python2 and Python3 < 3.2 compatibility
    if not hasattr(wrapped, "__wrapped__"):
        wrapped.__wrapped__ = func

    return wrapped


@my_decorator
def testing(msg):
    print("We got: %s" % msg)

decorate_test.py

# For some reason (maybe the decorator accesses resources which aren't
# available in the test environment), when we unittest, we want to test
# the function without its decoration.

import functools

try:
    from unittest import mock
except:
    import mock

import pytest

import decorate


# We want to replace the real decorator with one that doesn't do anything.
# In a real test, this decorator might do something like record how many
# times it was called.
def mock_decorator(func):
    @functools.wraps(func)
    def wrapped(*args, **kwargs):
        print("In mock decorator")
        return func(*args, **kwargs)

    return wrapped


# This way does not work because the decorator is applied when "testing"
# Is defined.  So monkeypatching the decorator at this point is too late.
# The Python interpreter has already defined "testing" when it imported
# "decorate" on line 14.

@pytest.fixture
def m_dec(monkeypatch):
    monkeypatch.setattr(decorate, "my_decorator", mock_decorator)


def test_monkeypatching_decorator(capsys, m_dec):
    print("In test function")

    decorate.testing("Tested")

    stdout = capsys.readouterr().out
    assert "In real decorator" not in stdout
    assert "In mock decorator" in stdout


# This way will work because it finds the original function (The undecorated "testing")
# and wraps it in our decorator that does nothing instead of the real decorator.
@pytest.fixture
def rewrap(monkeypatch):
    original_func = decorate.testing.__wrapped__
    print(id(decorate.testing))
    print(original_func)
    print(original_func.__name__)
    print(id(original_func))
    monkeypatch.setattr(decorate, "testing", mock_decorator(original_func))
    print(id(decorate.testing))


def test_rewrap_decorated_function(capsys, rewrap):

    decorate.testing("Tested")

    stdout = capsys.readouterr().out
    assert "In real decorator" not in stdout
    assert "In mock decorator" in stdout