test: improvements

Improved the test so that they didn't fail with my new implementation. Most changes is from `assert(a === b)` to `assert.equal(a, b)` which makes the output much clearer on what went wrong.

I still have some cleaning up to do on my code but hopefully I can soon submit the client/server refactoring, right now I need to get some sleep thought :)
Any particular reason for splitting this out into its own variable?

`mockStream.write(...)` looks ~just as clean to me.