Support async tests

[akiroz]

CLJS code is often async, maybe provide a =async=> that expects a checker on the RHS with a callback passed in?

[ragnorak1000]

Do you have an example in mind that you would like to see work?

[akiroz]

I was actually thinking of something like this:

(defn fetch-foo []
  (.resolve js/Promise :foo))

(defn promise-of [thing]
  (fn [result done]
    (-> result
        (.then #(= % thing))
        (.then done))))

(fact "Can fetch foo asynchronously"
  (fetch-foo) =async=> (promise-of :foo))