How to use doctest with a decorated function in python?

doctest, python, python-decorators, python-unittest

Solution

How about we side-step the problem by using a `memo` decorator which returns a function instead of a class instance:

import functools

def decorator(d):
    """Make function d a decorator: d wraps a function fn.
    Authors: Peter Norvig and Darius Bacon"""
    def _d(fn):
        return functools.update_wrapper(d(fn), fn)
    functools.update_wrapper(_d, d)
    return _d

@decorator
def memo(f):
    # by Peter Norvig
    """Decorator that caches the return value for each call to f(args).
    Then when called again with same args, we can just look it up."""
    cache = {}

    def _f(*args):
        try:
            return cache[args]
        except KeyError:
            cache[args] = result = f(*args)
            return result
        except TypeError:
            # some element of args can't be a dict key
            return f(*args)
    _f.cache = cache
    return _f

@memo
def is_tile_inside_border(x, y, z, border):
    '''Checks if a tile is inside border or not
    >>> is_tile_inside_border(85,53,7,'iran')
    3
    >>> is_tile_inside_border(85,15,7,'iran')
    0
    '''
    # binary_data = get_border_binary(border, z)
    # return isInside((x, y), binary_data)
    return True

class Foo(object):
    @memo
    def bar(self, x):
        """
        >>> Foo().bar(1)
        2
        """
        return x

if __name__ == '__main__':
    import doctest
    doctest.testmod()

Problem

Original source

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