client/site_tests/network_WlanRegulatory/network_WlanRegulatory.py

# Copyright (c) 2014 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import logging
import time

from autotest_lib.client.bin import test
from autotest_lib.client.common_lib import error
from autotest_lib.client.common_lib.cros.network import iw_runner


class network_WlanRegulatory(test.test):
    """
    Ensure the "crda" tool works, and can be successfully triggered by
    the kernel from the "iw" userspace utility to change the system
    regulatory domain.
    """
    version = 1
    TEST_REGULATORY_DOMAINS = ( 'CA', 'US' )

    def find_test_domain(self, not_these):
        """Select a test regulatory domain excluding |not_these|.

        @param not_these iterable of regulatory domains to exclude.
        @returns string Regulatory domain from |TEST_REGULATORY_DOMAINS|.

        """
        return list(set(self.TEST_REGULATORY_DOMAINS) - set(not_these))[0]


    def assert_set_regulatory_domain(self, regdomain):
        """Set the system regulatory domain, then assert that it is correct.

        @param regdomain string 2-letter country code of the regulatory
            domain to set.

        """
        logging.info('Using iw to set regulatory domain to %s', regdomain)
        self._iw.set_regulatory_domain(regdomain)

        # It takes time for the kernel to invoke udev, which will in turn
        # invoke CRDA.  Since this is asynchronous with the exit of the
        # "iw" utility, we must wait a while.
        time.sleep(2)

        current_regdomain = self._iw.get_regulatory_domain()
        if current_regdomain != regdomain:
            raise error.TestFail('Expected iw to set regdomain %s but got %s' %
                                 (regdomain, current_regdomain))


    def run_once(self):
        """Test main loop"""
        self._iw = iw_runner.IwRunner()
        initial_regdomain = self._iw.get_regulatory_domain()
        logging.info('Initial regulatory domain is %s', initial_regdomain)

        alternate_regdomain = self.find_test_domain([initial_regdomain])
        self.assert_set_regulatory_domain(alternate_regdomain)
        self.assert_set_regulatory_domain(initial_regdomain)