How to test Python 3.4 asyncio code?

Question

What\'s the best way to write unit tests for code using the Python 3.4 asyncio library? Assume I want to test a TCP client (SocketConnection):

Answer 1

You can also use aiounittest that takes similar approach as @Andrew Svetlov, @Marvin Killing answers and wrap it in easy to use AsyncTestCase class:

import asyncio
import aiounittest


async def add(x, y):
    await asyncio.sleep(0.1)
    return x + y

class MyTest(aiounittest.AsyncTestCase):

    async def test_async_add(self):
        ret = await add(5, 6)
        self.assertEqual(ret, 11)

    # or 3.4 way
    @asyncio.coroutine
    def test_sleep(self):
        ret = yield from add(5, 6)
        self.assertEqual(ret, 11)

    # some regular test code
    def test_something(self):
        self.assertTrue(true)

As you can see the async case is handled by AsyncTestCase. It supports also synchronous test. There is a possibility to provide custom event loop, just override AsyncTestCase.get_event_loop.

If you prefer (for some reason) the other TestCase class (eg unittest.TestCase), you might use async_test decorator:

import asyncio
import unittest
from aiounittest import async_test


async def add(x, y):
    await asyncio.sleep(0.1)
    return x + y

class MyTest(unittest.TestCase):

    @async_test
    async def test_async_add(self):
        ret = await add(5, 6)
        self.assertEqual(ret, 11)