ratbag-emu server fixture with random port

ratbag-emu-server-fixture.py

@pytest.fixture(autouse=True, scope='session')
@pytest.mark.first
def server(self, port_range=[9000, 9999]):
    p = port = None
    try:
        stdout = open('ratbag-emu-log-stdout.txt', 'w')
        stderr = open('ratbag-emu-log-stderr.txt', 'w')

        def try_port(port):
            ret = False
            try:
                sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                sock.bind(('0.0.0.0', port))
                ret = True
            finally:
                sock.close()
            return ret

        tries = 0
        found = False
        while not found:
            port = random.randint(port_range[0], port_range[1])
            found = try_port(port)
            tries += 1
            assert tries < 100, 'Reached max tries when trying to find a port'

        p = subprocess.Popen(['/usr/bin/env', 'python3', '-m', 'ratbag_emu', '-p', str(port)],
                             stdout=stdout, stderr=stderr)
        sleep(2)
        yield port
    finally:
        if p:
            p.kill()
        if stdout:
            stdout.close()
        if stderr:
            stderr.close()