With the addition of asyncio in the Python 3.4 stdlib and the async/await syntax in Python 3.5, co-operative asynchronous programing is now an official part of Python. The co-operative asynchronous mode is not complicated to use - but the Python ecosystem is a bit confusing at first. Here I give an introduction to asynchronous programing concepts and eco-system in Python.

The asyncio library introduced in Python 3.4 allows us to write concurrent code running, amongst other things, network clients and servers. Here I show how to unit-test asyncio code to ensure it is possible to use it over an SSL connection.