Howto do unittest for tornado + async def? - unit-testing

Question

Environment: Python 3, tornado 4.4. The normal unittests cannot be used because methods are asynchronous. There is ttp://www.tornadoweb.org/en/stable/testing.html that explains how to do unit testing for asynchronous code. But that works with tornado coroutines ONLY. The classes I want to test are using the async def statements, and they cannot be tested this way. For example, here is a test case that uses ASyncHTTPClient.fetch and its callback parameter:
class MyTestCase2(AsyncTestCase):
def test_http_fetch(self):
client = AsyncHTTPClient(self.io_loop)
client.fetch("http://www.tornadoweb.org/", self.stop)
response = self.wait()
# Test contents of response
self.assertIn("FriendFeed", response.body)
But my methods are declared like this:
class Connection:
async def get_data(url, *args):
# ....
And there is no callback. How can I "await" for this method from a test case?
UPDATE: based on Jessie's answer, I created this MWE:
import unittest
from tornado.httpclient import AsyncHTTPClient
from tornado.testing import AsyncTestCase, gen_test, main
class MyTestCase2(AsyncTestCase):
#gen_test
async def test_01(self):
await self.do_more()
async def do_more(self):
self.assertEqual(1+1, 2)
main()
The result is this:
>py -3 -m test.py
E
======================================================================
ERROR: all (unittest.loader._FailedTest)
----------------------------------------------------------------------
AttributeError: module '__main__' has no attribute 'all'
----------------------------------------------------------------------
Ran 1 test in 0.000s
FAILED (errors=1)
[E 170205 10:05:43 testing:731] FAIL
There is no traceback. But if I replace tornado.testing.main() with unittest.main() then it suddenly starts working.
But why? I guessed that for asnyc unit tests, I need to use tornado.testing.main ( http://www.tornadoweb.org/en/stable/testing.html#tornado.testing.main )
I'm confused.
UPDATE 2: It is a bug in tornado.testing. Workaround:
all = MyTestCase2
main()

Answer 1

Instead of using the self.wait / self.stop callbacks, you can wait for "fetch" to complete by using it in an "await" expression:
import unittest
from tornado.httpclient import AsyncHTTPClient
from tornado.testing import AsyncTestCase, gen_test
class MyTestCase2(AsyncTestCase):
#gen_test
async def test_http_fetch(self):
client = AsyncHTTPClient(self.io_loop)
response = await client.fetch("http://www.tornadoweb.org/")
# Test contents of response
self.assertIn("FriendFeed", response.body.decode())
unittest.main()
The other change I had to make in your code is to call "decode" on the body in order to compare the body (which is bytes) to "FriendFeed" which is a string.