Add an exitOnClose function to the "pub serve" WebSocket API.

sdk/lib/_internal/pub/test/serve/utils.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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 pub_tests;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
@@ skipping 310 matching lines @@
   expect(_pubServer, isNotNull);
   expect(_adminPort, isNotNull);
 
   return WebSocket.connect("ws://127.0.0.1:$_adminPort").then((socket) {
     _webSocket = socket;
     // TODO(rnystrom): Works around #13913.
     _webSocketBroadcastStream = _webSocket.map(JSON.decode).asBroadcastStream();
   });
 }
 
+/// Schedules closing the web socket connection to the currently-running pub
+/// serve.
+Future closeWebSocket() {
+  schedule(() {
+    return _ensureWebSocket().then((_) => _webSocket.close())
+        .then((_) => _webSocket = null);
+  }, "closing web socket");
+}
+
 /// Sends a JSON RPC 2.0 request to the running pub serve's web socket
 /// connection.
 ///
-/// This calls a method named [method] with the given [params]. [params] may
-/// contain Futures, in which case this will wait until they've completed before
-/// sending the request.
+/// This calls a method named [method] with the given [params] (or no
+/// parameters, if it's not passed). [params] may contain Futures, in which case
+/// this will wait until they've completed before sending the request.
 ///
 /// This schedules the request, but doesn't block the schedule on the response.
 /// It returns the response as a [Future].
-Future<Map> webSocketRequest(String method, Map params) {
+Future<Map> webSocketRequest(String method, [Map params]) {
   var completer = new Completer();
   schedule(() {
     return Future.wait([
       _ensureWebSocket(),
       awaitObject(params),
     ]).then((results) {
       var resolvedParams = results[1];
       chainToCompleter(
           currentSchedule.wrapFuture(_jsonRpcRequest(method, resolvedParams)),
           completer);
@@ skipping 66 matching lines @@
     expect(_ports.containsKey(root), isFalse);
   });
 }
 
 /// The next id to use for a JSON-RPC 2.0 request.
 var _rpcId = 0;
 
 /// Sends a JSON-RPC 2.0 request calling [method] with [params].
 ///
 /// Returns the response object.
-Future<Map> _jsonRpcRequest(String method, Map params) {
+Future<Map> _jsonRpcRequest(String method, [Map params]) {
   var id = _rpcId++;
-  _webSocket.add(JSON.encode({
+  var message = {
     "jsonrpc": "2.0",
     "method": method,
-    "params": params,
     "id": id
-  }));
+  };
+  if (params != null) message["params"] = params;
+  _webSocket.add(JSON.encode(message));
 
   return _webSocketBroadcastStream
       .firstWhere((response) => response["id"] == id).then((value) {
     currentSchedule.addDebugInfo(
         "Web Socket request $method with params $params\n"
         "Result: $value");
 
     expect(value["id"], equals(id));
     return value;
   });
@@ skipping 22 matching lines @@
 /// included. Unlike [getServerUrl], this should only be called after the ports
 /// are known.
 String _getServerUrlSync([String root, String path]) {
   if (root == null) root = 'web';
   expect(_ports, contains(root));
   var url = "http://127.0.0.1:${_ports[root]}";
   if (path != null) url = "$url/$path";
   return url;
 }