def _relpath_posix(path, start=os.path.curdir):

    if not path:
        raise ValueError("no path specified")

    start_list = os.path.abspath(start).split(os.path.sep)
    path_list = os.path.abspath(path).split(os.path.sep)

    # Work out how much of the filepath is shared by start and path.
    i = len(os.path.commonprefix([start_list, path_list]))

    rel_list = [os.path.pardir] * (len(start_list)-i) + path_list[i:]
    if not rel_list:
        return os.path.curdir
    return os.path.join(*rel_list)
Test VXLAN bind_port processing.
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.3/django/utils/unittest/compatibility.py/_relpath_posix--crossover with--dataset/ETHPy150Open openstack/networking-cisco/networking_cisco/tests/unit/ml2/drivers/cisco/nexus/test_cisco_mech.py/TestCiscoPortsV2.test_nexus_vxlan_bind_port_no_dynamic_segment