v2.0.x Chore - DRY via setup/teardown for contexts in test

[reactive-firewall]

Consider moving process management to setUp/tearDown

The process creation, monitoring, and cleanup logic is duplicated across test methods. Consider refactoring this into setUp/tearDown methods for better maintainability.

def setUp(self):
    self._fixture_port_num = self._always_generate_random_port_WHEN_called()
    self.assertIsNotNone(self._fixture_port_num)
    self.assertIsInstance(self._fixture_port_num, int)
    self.process = None

def tearDown(self):
    if self.process and self.process.is_alive():
        self.process.terminate()
        self.process.close()

def _start_process(self, daemon=False):
    _fixture_HEAR_args = [
        "--port", str(self._fixture_port_num),
        "--groups", "'224.0.0.1'",
        "--group", "'224.0.0.1'"
    ]
    args = ["--daemon", "HEAR"] if daemon else ["RECV"]
    args.extend(_fixture_HEAR_args)
    self.process = Process(
        target=multicast.__main__.main,
        name="HEAR" if daemon else "RECV",
        args=tuple(args)
    )
    self.process.start()
    self.assertIsNotNone(self.process)