A context to change current working directory.

# a context to change working directory
# tested with python 2.6 and 3.1. For 2.5, uncomment this:
# from __future__ import with_statement
from contextlib import contextmanager
import os

@contextmanager
def WorkingDirectory(dst_dir):
    dst_dir = os.path.abspath(
            os.path.normpath(
            os.path.expanduser(
            os.path.expandvars(dst_dir))))
    current_dir = os.getcwd()
    os.chdir(dst_dir)
    try:
        yield dst_dir
    finally:
        os.chdir(current_dir)


if __name__ == "__main__":
    # test code
    with WorkingDirectory(".."):
        # code in this with block is executed with
        # the parent dir as current working directory
        print(os.getcwd())
    # after the with block, we are back in the
    # initial working directory. This is also
    # true if an exception is raised inside the with block.
    print(os.getcwd())