Set up Laravel 5.4 with Dusk using phpunit.xml, .env.dusk.local, and an sqlite in-memory database
You cannot.
The important thing to note is that for this kind of end-to-end test, Dusk will not be able to control the environment as it will open a separate process. An in-memory SQLite would only exists under Dusk process and the real-browser hitting the application would have no knowledge of the database Dusk created, making it impossible to assert anything in the database.