Vapor 2 brings many improvements to the framework and one of the most significant revolves around testing. Josh Justice from Big Nerd Ranch explores how you should test your web application using Request Testing, as opposed to testing a class's API directly.
In Type-Driven Development you focus on the types of your functions before implementing them. After the types compile, you go back and write the actual code. This gives you a proven foundation for your code. I haven't spent much time researching this deeply, but it looks interesting anyway. There's also a video from one NSLondon meetup that talks about it.
ApacheExpress is a technology demo which shows how to write native modules for the Apache Web Server.