Merge pull request #1874 from karol-f/wip/master/server_port

feat(server): add 'listening' event with port number

docs/dev/04-public-api.md

@@ -40,6 +40,13 @@ server.on('browser_register', function (browser) {
 })
 ```
 
+### `listening`
+**Arguments:**
+
+* `port`: Port number
+
+Begin accepting connections on the specified port.
+
 ### `browser_register`
 **Arguments:**
 

lib/server.js

@@ -167,6 +167,8 @@ Server.prototype._start = function (config, launcher, preprocess, fileList, webS
       self.log.info('Karma v%s server started at %s//%s:%s%s', constant.VERSION,
         config.protocol, config.hostname, config.port, config.urlRoot)
 
+      self.emit('listening', config.port)
+
       if (config.browsers && config.browsers.length) {
         self._injector.invoke(launcher.launch, launcher).forEach(function (browserLauncher) {
           singleRunDoneBrowsers[browserLauncher.id] = false

test/unit/server.spec.js

@@ -149,6 +149,19 @@ describe('server', () => {
       expect(mockConfig.port).to.be.equal(9877)
     })
 
+    it('should emit a listening event once server begin accepting connections', () => {
+      server._start(mockConfig, mockLauncher, null, mockFileList, mockWebServer, browserCollection, mockSocketServer, mockExecutor, doneSpy)
+
+      var listening = sinon.spy()
+      server.on('listening', listening)
+
+      expect(listening).not.to.have.been.called
+
+      fileListOnResolve()
+
+      expect(listening).to.have.been.calledWith(9876)
+    })
+
     it('should emit a browsers_ready event once all the browsers are captured', () => {
       server._start(mockConfig, mockLauncher, null, mockFileList, mockWebServer, browserCollection, mockSocketServer, mockExecutor, doneSpy)