build: prevent binding BrowserSync UI server during test execution

Author: trik

tools/dev-server/dev-server.ts

@@ -38,8 +38,12 @@ export class DevServer {
   };
 
   constructor(
-      readonly port: number, private _rootPaths: string[],
-      private _historyApiFallback: boolean = false) {}
+    readonly port: number, private _rootPaths: string[], bindUi: boolean,
+    private _historyApiFallback: boolean = false) {
+    if (bindUi === false) {
+      this.options.ui = false;
+    }
+  }
 
   /** Starts the server on the given port. */
   start() {

tools/dev-server/ibazel.ts

@@ -12,14 +12,18 @@ import {DevServer} from './dev-server';
 // ibazel will write this string after a successful build.
 const ibazelNotifySuccessMessage = 'IBAZEL_BUILD_COMPLETED SUCCESS';
 
+export function isIBazelProcess() {
+  return process.env['IBAZEL_NOTIFY_CHANGES'] === 'y';
+}
+
 /**
  * Sets up ibazel support for the specified devserver. ibazel communicates with
  * an executable over the "stdin" interface. Whenever a specific message is sent
  * over "stdin", the devserver can be reloaded.
  */
 export function setupBazelWatcherSupport(server: DevServer) {
   // If iBazel is not configured for this process, we do not setup the watcher.
-  if (process.env['IBAZEL_NOTIFY_CHANGES'] !== 'y') {
+  if (!isIBazelProcess()) {
     return;
   }
 

tools/dev-server/main.ts

@@ -9,14 +9,15 @@
 import minimist from 'minimist';
 
 import {DevServer} from './dev-server';
-import {setupBazelWatcherSupport} from './ibazel';
+import {isIBazelProcess, setupBazelWatcherSupport} from './ibazel';
 
 const args = process.argv.slice(2);
 const {root_paths: _rootPathsRaw, port, historyApiFallback} =
     minimist(args, {boolean: 'historyApiFallback'});
 const rootPaths = _rootPathsRaw ? _rootPathsRaw.split(',') : ['/'];
 
-const server = new DevServer(port, rootPaths, historyApiFallback);
+const bindUi = isIBazelProcess();
+const server = new DevServer(port, rootPaths, bindUi, historyApiFallback);
 
 // Setup ibazel support.
 setupBazelWatcherSupport(server);