def METHOD_NAME(self):
    tf = tempfile.NamedTemporaryFile()
    try:
        before = self._get_cpus()
        self.policy._set_cpu(None, 3)
        my_cpu = self._get_cpus()
        proc = mitogen.parent.popen(
            args=['cp', '/proc/self/status', tf.name]
        )
        proc.wait()
        his_cpu = self._get_cpus(tf.name)
        self.assertNotEqual(my_cpu, his_cpu)
        self.policy._clear()
    finally:
        tf.close()