What is the best way to test events?

[marcelomorgado]

Should we keep using mocha done function or should we use some specific tool for that?
Refs:
https://stackoverflow.com/questions/16826352/whats-the-best-way-to-unit-test-an-event-being-emitted-in-nodejs
https://www.npmjs.com/package/chai-events

Extracted from: #369 (comment)

[pcowgill]

Alternatively, we can create our own custom test helper that still uses done() internally but is named something like "assert error listener triggered", etc.