Asynchronous Testing Decorator

Provides a Python decorator, which you can incorporate into your project, that allows you to easily test code that uses Python's asyncio infrastructure with the standard unittest library.

Installation

Presuming your Python project is under Git source control:

git remote add async-test https://github.com/wtsi-hgi/async-test.git
git fetch async-test
git merge --allow-unrelated-histories --no-commit async-test/src
git mv async.py wherever/you/want/it/to/go
git commit --no-edit
git remote remove async-test

This merges the decorator's Git history into your repository's current branch, from the src branch which contains just async.py in its root. (Note that if your repository contains an async.py in its root, you will have to sort out merge conflicts.) The git mv step then moves the module to wherever is convenient for you within your repository.

Usage

Import the async_test function into any testing module and use it as a decorator for any test cases you may have:

import unittest
from .async import async_test

class TestMyAsyncThingy(unittest.TestCase):
  @async_test
  async def test_something(self):
    foo = await something()
    self.assertEqual(foo, "bar")

The decorator can be used bare, as in the above example, or it can be parametrised with a specific event loop:

import asyncio
import unittest
from .async import async_test

my_event_loop = asyncio.get_event_loop()

class TestMyAsyncThingy(unittest.TestCase):
  @async_test(my_event_loop)
  async def test_something(self):
    foo = await something()
    self.assertEqual(foo, "bar")

The decorator works by wrapping the test case function up as a coroutine and then running it until completion within the (optionally specified) event loop.