88     def send(cls, cmd):  argument
89         if cls.process is None:
93         cls.process.stdin.write(cmd)
94         cls.process.stdin.flush()
97     def read_until(cls, marker):  argument
107             not cls.exit_event.is_set()
110                 char = cls.process.stdout.read(1)
143         if cls.exit_event.is_set():
151     def setUpClass(cls):  argument
153         cls.exit_event = threading.Event()
156         cls.process = subprocess.Popen(
167         cls.send(b'cd ' + os.path.dirname(__file__).encode('utf-8') + b'\n')
168         cls.send(MICROPYTHON_PATH.encode('utf-8') + b'\n')
169         _, error_data = cls.read_until(b'>>>')
177     def tearDownClass(cls):  argument
180         if cls.process is not None:
181             cls.send(CTRL_C)
182             cls.send(CTRL_C)
183             cls.send(CTRL_D)
185             if not cls.process.stdin.closed:
186                 cls.process.stdin.close()
188             os.killpg(os.getpgid(cls.process.pid), signal.SIGTERM)
190             cls.process.wait()
192             if not cls.process.stdout.closed:
193                 cls.process.stdout.close()
195             if not cls.process.stderr.closed:
196                 cls.process.stderr.close()
198             cls.process = None