fix: add callback to pubsub.unsubscribe and test (#300)

src/pubsub.js

@@ -33,7 +33,7 @@ module.exports = (node) => {
       subscribe(callback)
     },
 
-    unsubscribe: (topic, handler) => {
+    unsubscribe: (topic, handler, callback) => {
       if (!node.isStarted() && !floodSub.started) {
         throw new Error(NOT_STARTED_YET)
       }
@@ -43,6 +43,10 @@ module.exports = (node) => {
       if (floodSub.listenerCount(topic) === 0) {
         floodSub.unsubscribe(topic)
       }
+
+      if (typeof callback === 'function') {
+        setImmediate(() => callback())
+      }
     },
 
     publish: (topic, data, callback) => {

test/pubsub.node.js

@@ -5,9 +5,10 @@
 
 const chai = require('chai')
 chai.use(require('dirty-chai'))
+chai.use(require('chai-checkmark'))
 const expect = chai.expect
 const parallel = require('async/parallel')
-const waterfall = require('async/waterfall')
+const series = require('async/series')
 const _times = require('lodash.times')
 
 const createNode = require('./utils/create-node')
@@ -52,26 +53,37 @@ function stopTwo (nodes, callback) {
 // TODO: consider if all or some of those should come here
 describe('.pubsub', () => {
   describe('.pubsub on (default)', (done) => {
-    it('start two nodes and send one message', (done) => {
-      waterfall([
-        (cb) => startTwo(cb),
-        (nodes, cb) => {
-          const data = Buffer.from('test')
-          nodes[0].pubsub.subscribe('pubsub',
-            (msg) => {
-              expect(msg.data).to.eql(data)
-              cb(null, nodes)
-            },
-            (err) => {
-              expect(err).to.not.exist()
-              setTimeout(() => nodes[1].pubsub.publish('pubsub', data, (err) => {
-                expect(err).to.not.exist()
-              }), 500)
-            }
-          )
-        },
-        (nodes, cb) => stopTwo(nodes, cb)
-      ], done)
+    it('start two nodes and send one message, then unsubscribe', (done) => {
+      // Check the final series error, and the publish handler
+      expect(2).checks(done)
+
+      let nodes
+      const data = Buffer.from('test')
+      const handler = (msg) => {
+        // verify the data is correct and mark the expect
+        expect(msg.data).to.eql(data).mark()
+      }
+
+      series([
+        // Start the nodes
+        (cb) => startTwo((err, _nodes) => {
+          nodes = _nodes
+          cb(err)
+        }),
+        // subscribe on the first
+        (cb) => nodes[0].pubsub.subscribe('pubsub', handler, cb),
+        // Wait a moment before publishing
+        (cb) => setTimeout(cb, 500),
+        // publish on the second
+        (cb) => nodes[1].pubsub.publish('pubsub', data, cb),
+        // unsubscribe on the first
+        (cb) => nodes[0].pubsub.unsubscribe('pubsub', handler, cb),
+        // Stop both nodes
+        (cb) => stopTwo(nodes, cb)
+      ], (err) => {
+        // Verify there was no error, and mark the expect
+        expect(err).to.not.exist().mark()
+      })
     })
   })