add a very simply unit test of our publisher/subscriber system in metabase.events

test/metabase/events_test.clj

+(ns metabase.events-test
+  (:require [clojure.core.async :as async]
+            [expectations :refer :all]
+            [metabase.events :as events]
+            (metabase [task :refer :all]
+                      [test-setup :refer :all])))
+
+(def testing-topic :event-test-topic)
+
+(def testing-sub-channel (async/chan))
+
+
+;; ## Basic Pub/Sub TESTS
+
+(events/subscribe-to-topic testing-topic testing-sub-channel)
+
+;; we should get back our originally posted object no matter what happens
+(expect
+  {:some :object}
+  (events/publish-event testing-topic {:some :object}))
+
+;; when we receive a message it should be wrapped with {:topic `topic` :item `message body`}
+(expect
+  {:topic testing-topic
+   :item  {:some :object}}
+  (async/<!! testing-sub-channel))