Sanitize a file path against directory traversal in python

sanitize.py

import os.path

def sanitize_path(path):
    """
    Sanitize a path against directory traversals
    
    Based on https://stackoverflow.com/questions/13939120/sanitizing-a-file-path-in-python.

    >>> sanitize_path('../test')
    'test'
    >>> sanitize_path('../../test')
    'test'
    >>> sanitize_path('../../abc/../test')
    'test'
    >>> sanitize_path('../../abc/../test/fixtures')
    'test/fixtures'
    >>> sanitize_path('../../abc/../.test/fixtures')
    '.test/fixtures'
    >>> sanitize_path('/test/foo')
    'test/foo'
    >>> sanitize_path('./test/bar')
    'test/bar'
    >>> sanitize_path('.test/baz')
    '.test/baz'
    >>> sanitize_path('qux')
    'qux'
    """
    # - pretending to chroot to the current directory
    # - cancelling all redundant paths (/.. = /)
    # - making the path relative
    return os.path.relpath(os.path.join("/", path), "/")

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