Integration tests needed

[Altreus]

I've been putting off behavioural tests - integration tests, I guess - because I don't know how to achieve it.

What we really need to be able to test is how the system behaves in various scenarios from Discord itself.

The prime target for that is connectivity. We have been having trouble with reconnecting (#41) after unknown events (net drop? forced disconnection?) and so we want to have a test library that will pretend to be Discord for the WebSocket class.

• Faux Discord server for integration tests
• E2E testing of scenarios:
  • Message sent/received
    • including embeds
  • Reactions added/removed
  • Member joins/leaves
• Unit tests for all classes

More to be added as I think of it