RC0 Testing Guidelines?

My app has become quite big. I have been fiddling with test for a while, but it has never quite worked well.

Now with the RC0 i wonder if there is any Testing strategies in place.
I am excited with rollup.js but do not know anything about it yet.
Maybe a sample-app we could borrow from?

I used a testing configuration in beta11 similar to lathonez’s one and it worked like a charm. I’m looking for some examples too to avoid figuring out a new configuration from scratch. I will post here if I find something useful.

Edit: this seems to be an interesting discussion https://github.com/lathonez/clicker/issues/148