Fix updateNode being called with undefined rootNode

[simonihmig]

When redux dispatch() is called before getState() has ever been called, updateNode() (in the custom creatStore() function) will be called with rootNode still undefined.

This wasn't catched in tests as they coincidentally always called getState() (for the cache setup) before dispatching. The added test here reproduces the bug that I was seeing when that's not the case.

[simonihmig]

First of all I should actually say how great this is! 🚀

I assume this was influenced/triggered by the discussion you had with my teammate @lolmaus in RFC 566. Finally I found the time to try this out in our codebase (an internal shared addon) where we used ember-redux before, and the refactoring using tracked-redux seems to work really nicely (ignoring this little bug)! Especially the fact that memoization now works automatically for any nested props, whereas before using CPs the caching effect would not work at all even with their explicit dependencies because the immutable nature of the redux state would invalidate every time even if their dependencies have actually not changed.

This is now much better, so thanks a lot for your tireless effort to bring us all the benefits of autotracking! 😍

[simonihmig]

CI is failing for unrelated reasons, #3 should fix this.

[pzuraq]

I believe the way that I'm patching the store is actually wrong, and can be done better with middleware. I just haven't had the time to actually dig in and fix it, unfortunately. That said, if this fixes the problem then I'm all for it

[simonihmig]

Rebased, green now.