异步单元测试Sanic应用程序抛出运行时错误：此事件循环已在运行

Question

我有一个Sanic应用程序，可以对外部api进行异步调用。我希望编写一些模拟这些外部调用的单元测试。在

在下面的代码中，我们可以从日志中看到测试通过了。但是，在它们完成一个RuntimeError之后：抛出这个已经在运行的事件循环

简化的Sanic应用程序：

app = Sanic(__name__)
app.config.from_pyfile('/usr/src/app/config.py')
Initialize(
    app,
    access_token_name='jwt',
    authenticate=lambda: True,
    claim_aud=app.config.AUTH_JWT_TOKEN['service']['audience'],
    claim_iss=app.config.AUTH_JWT_TOKEN['service']['issuer'],
    public_key=app.config.AUTH_JWT_TOKEN['service']['secret'],
    responses_class=JWTResponses
)


@app.listener('before_server_start')
def init(app, loop):
    ssl_ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
    ssl_ctx.load_cert_chain(app.config.SSL_CERT, app.config.SSL_CERT_KEY)
    ssl_ctx.load_verify_locations(app.config.SSL_SERVER_CERT)
    ssl_ctx.check_hostname = False
    ssl_ctx.verify_mode = ssl.CERT_REQUIRED
    conn = aiohttp.TCPConnector(ssl_context=ssl_ctx)
    app.aiohttp_session = aiohttp.ClientSession(loop=loop, connector=conn)
    access_logger.disabled = True


@app.listener('after_server_stop')
def finish(app, loop):
    loop.run_until_complete(app.aiohttp_session.close())
    loop.close()


@app.route("endpoint/<mpn>")
@protected()
async def endpoint(request, mpn):
    msg = msg(
        mpn,
    )
    headers = {'content-type': 'text/xml'}
    async with session.post(
        config.URL,
        data=msg.tostring(pretty_print=True, encoding='utf-8'),
        headers=headers,
    ) as response:
        response_text = await response.text()
        try:
            response = (
                Response.from_xml(response_text)
            )
            return response
        except ResponseException:
            logger.error(e.get_message()['errors'][0]['message'])
            return response.json(
                e.get_message(),
                status=HTTPStatus.INTERNAL_SERVER_ERROR
            )


if __name__ == '__main__':
    app.run(host="0.0.0.0", port=8000)

测试如下：

^{pr2}$

如上所述，测试确实通过，但随后抛出错误。在

================================================================================================= ERRORS ==================================================================================================
____________________________________________________________________________________ ERROR at teardown of test_success ____________________________________________________________________________________

tp = <class 'RuntimeError'>, value = None, tb = None

    def reraise(tp, value, tb=None):
        try:
            if value is None:
                value = tp()
            if value.__traceback__ is not tb:
                raise value.with_traceback(tb)
>           raise value
/usr/local/lib/python3.6/site-packages/six.py:693:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
/usr/local/lib/python3.6/site-packages/six.py:693: in reraise
    raise value
/usr/local/lib/python3.6/site-packages/six.py:693: in reraise
    raise value
/usr/local/lib/python3.6/site-packages/pytest_sanic/plugin.py:212: in sanic_client
    loop.run_until_complete(client.close())
uvloop/loop.pyx:1451: in uvloop.loop.Loop.run_until_complete
    ???
/usr/local/lib/python3.6/site-packages/pytest_sanic/utils.py:230: in close
    await self._server.close()
/usr/local/lib/python3.6/site-packages/pytest_sanic/utils.py:134: in close
    await trigger_events(self.after_server_stop, self.loop)
/usr/local/lib/python3.6/site-packages/pytest_sanic/utils.py:25: in trigger_events
    result = event(loop)
server.py:84: in finish
    loop.run_until_complete(app.aiohttp_session.close())
uvloop/loop.pyx:1445: in uvloop.loop.Loop.run_until_complete
    ???
uvloop/loop.pyx:1438: in uvloop.loop.Loop.run_until_complete
    ???
uvloop/loop.pyx:1347: in uvloop.loop.Loop.run_forever
    ???
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

>   ???
E   RuntimeError: this event loop is already running.

uvloop/loop.pyx:448: RuntimeError

如有任何帮助或建议，我们将不胜感激。提前谢谢

Answer 1

我认为您可以通过更改此方法来修复错误：

@app.listener('after_server_stop')
async def finish(app, loop):
    await app.aiohttp_session.close()

关闭循环不是您的责任，您应该使用这样一个事实，即finish是从异步上下文调用的（不需要启动事件循环，它已经在运行）。在

如果这不是唯一的问题，那么也许从一个简单的例子开始，添加一些东西，直到它再次崩溃。Sanic似乎有一个很好的文档test section，他们建议使用pytest-sanic。使用pytest的一个简单示例如下：

^{pr2}$

# file: server_test.py
import pytest
from server import app

@pytest.yield_fixture
def sanic_app():
    yield app

@pytest.fixture
def test_cli(loop, sanic_app, sanic_client):
    return loop.run_until_complete(sanic_client(app))

async def test_index(test_cli):
    resp = await test_cli.get('/')
    assert resp.status == 200
    json = await resp.json()
    assert json == {'hello': 'world'}

async def test_index_fail(test_cli):
    resp = await test_cli.get('/')
    assert resp.status == 200
    json = await resp.json()
    assert json == {'bonjour': 'monde'}

您需要安装一些软件包：

pip install sanic pytest pytest-sanic

然后可以运行pytest，第一个测试通过，第二个测试失败。在

一般来说，您不必自己启动事件循环，始终尝试摆脱loop.run_...。在