Only load a certain number of test suites at once.

lib/src/runner/browser/static/host.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library test.runner.browser.host;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:html';
 import 'dart:js' as js;
 
 import 'package:stack_trace/stack_trace.dart';
 import 'package:test/src/util/multi_channel.dart';
 import 'package:test/src/util/stream_channel.dart';
 
+/// The iframes created for each loaded test suite, indexed by the suite id.
+final _iframes = new Map<int, IFrameElement>();
+
 // TODO(nweiz): test this once we can run browser tests.
 /// Code that runs in the browser and loads test suites at the server's behest.
 ///
 /// One instance of this runs for each browser. When the server tells it to load
 /// a test, it starts an iframe pointing at that test's code; from then on, it
 /// just relays messages between the two.
 ///
 /// The browser uses two layers of [MultiChannel]s when communicating with the
 /// server:
 ///
@@ skipping 41 matching lines @@
 /// the same place the client does.
 void main() {
   // This tells content_shell not to close immediately after the page has
   // rendered.
   var testRunner = js.context['testRunner'];
   if (testRunner != null) testRunner.callMethod('waitUntilDone', []);
 
   runZoned(() {
     var serverChannel = _connectToServer();
     serverChannel.stream.listen((message) {
-      assert(message['command'] == 'loadSuite');
-      var suiteChannel = serverChannel.virtualChannel(message['channel']);
-      var iframeChannel = _connectToIframe(message['url']);
-      suiteChannel.pipe(iframeChannel);
+      if (message['command'] == 'loadSuite') {
+        var suiteChannel = serverChannel.virtualChannel(message['channel']);
+        var iframeChannel = _connectToIframe(message['url'], message['id']);
+        suiteChannel.pipe(iframeChannel);
+      } else {
+        assert(message['command'] == 'closeSuite');
+        _iframes[message['id']].remove();
+      }
     });
   }, onError: (error, stackTrace) {
     print("$error\n${new Trace.from(stackTrace).terse}");
   });
 }
 
 /// Creates a [MultiChannel] connection to the server, using a [WebSocket] as
 /// the underlying protocol.
 MultiChannel _connectToServer() {
   // The `managerUrl` query parameter contains the WebSocket URL of the remote
   // [BrowserManager] with which this communicates.
   var currentUrl = Uri.parse(window.location.href);
   var webSocket = new WebSocket(currentUrl.queryParameters['managerUrl']);
 
   var inputController = new StreamController(sync: true);
   webSocket.onMessage.listen(
       (message) => inputController.add(JSON.decode(message.data)));
 
   var outputController = new StreamController(sync: true);
   outputController.stream.listen(
       (message) => webSocket.send(JSON.encode(message)));
 
   return new MultiChannel(inputController.stream, outputController.sink);
 }
 
 /// Creates an iframe with `src` [url] and establishes a connection to it using
 /// `postMessage`.
-StreamChannel _connectToIframe(String url) {
+///
+/// [id] identifies the suite loaded in this iframe.
+StreamChannel _connectToIframe(String url, int id) {
   var iframe = new IFrameElement();
+  _iframes[id] = iframe;
   iframe.src = url;
   document.body.children.add(iframe);
 
   var inputController = new StreamController(sync: true);
   var outputController = new StreamController(sync: true);
 
   // Use this to avoid sending a message to the iframe before it's sent a
   // message to us. This ensures that no messages get dropped on the floor.
   var readyCompleter = new Completer();
 
@@ skipping 15 matching lines @@
     if (!readyCompleter.isCompleted) readyCompleter.complete();
   });
 
   outputController.stream.listen((message) async {
     await readyCompleter.future;
     iframe.contentWindow.postMessage(message, window.location.origin);
   });
 
   return new StreamChannel(inputController.stream, outputController.sink);
 }