Twisted has been supporting asynchronous / event driven applications way before asyncio. Twisted, and Glyph, have also been encouraging automated tests for a very long time.

Twisted uses a technique that should be usable by other applications, even those using asyncio or other event driven architectures.

Links:

• Community Service Award Recipient Glyph Lefkowitz — The PSF article I was referring to early in the episode 
• Twisted
• twisted/klein
• twisted/treq
• django/daphne — Django Channels HTTP/WebSocket server
• Scrapy
• So Easy You Can Even Do It in JavaScript: Event-Driven Architecture for Regular Programmers - YouTube
• Feature test - twitter engineering
• Python Testing with pytest — Some reading for Glyph if he wants to learn to love pytest
• pytest-twisted
• pygame
• Pyodide
• Brython