Yes, that looks like a docker-compose config. But, it doesn't really matter. The point is that you could run MySQL in a way such that its storage (the actual data files) are on a virtual filesystem running in RAM.
It's a nice way to do it, IMO, because I prefer testing against a real DB instance in my projects anyway (rather than pretending that a unit test against a fake 'FooRepository' interface proves anything at all).
It's a nice way to do it, IMO, because I prefer testing against a real DB instance in my projects anyway (rather than pretending that a unit test against a fake 'FooRepository' interface proves anything at all).