Process outstanding events before making a new HTTP client request

tests/standalone/io/https_bad_certificate_client.dart

 // Copyright (c) 2013, 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.
 
 // Client for https_bad_certificate_test, that runs in a subprocess.
 // It verifies that the client bad certificate callback works in HttpClient.
 
 import "dart:async";
 import "dart:io";
 
 class ExpectException implements Exception {
   ExpectException(this.message);
   String toString() => "ExpectException: $message";
   String message;
 }
 
 void expect(condition) {
   if (!condition) {
     throw new ExpectException('');
   }
 }
 
 const HOST_NAME = "localhost";
 
-Future runHttpClient(int port, result) {
+Future runHttpClient(int port, result) async {
   bool badCertificateCallback(X509Certificate certificate,
                               String host,
                               int callbackPort) {
     expect(HOST_NAME == host);
     expect(callbackPort == port);
     expect('CN=localhost' == certificate.subject);
     expect('CN=myauthority' == certificate.issuer);
     expect(result != 'exception');  // Throw exception if one is requested.
     if (result == 'true') return true;
     if (result == 'false') return false;
     return result;
   }
 
   HttpClient client = new HttpClient();
 
-  var testFutures = [];  // The three async getUrl calls run simultaneously.
-  testFutures.add(client.getUrl(Uri.parse('https://$HOST_NAME:$port/$result'))
+  await client.getUrl(Uri.parse('https://$HOST_NAME:$port/$result'))
     .then((HttpClientRequest request) {
       expect(result == 'true');  // The session cache may keep the session.
       return request.close();
     }, onError: (e) {
       expect(e is HandshakeException || e is SocketException);
-    }));
+    });
 
   client.badCertificateCallback = badCertificateCallback;
-  testFutures.add(client.getUrl(Uri.parse('https://$HOST_NAME:$port/$result'))
+  await client.getUrl(Uri.parse('https://$HOST_NAME:$port/$result'))
     .then((HttpClientRequest request) {
       expect(result == 'true');
       return request.close();
     }, onError: (e) {
       if (result == 'false') expect (e is HandshakeException ||
                                      e is SocketException);
       else if (result == 'exception') expect (e is ExpectException ||
                                               e is SocketException);
-      else expect (e is ArgumentError || e is SocketException);
-    }));
+      else {
+        expect (e is ArgumentError || e is SocketException);
+      }
+    });
 
   client.badCertificateCallback = null;
-  testFutures.add(client.getUrl(Uri.parse('https://$HOST_NAME:$port/$result'))
+  await client.getUrl(Uri.parse('https://$HOST_NAME:$port/$result'))
     .then((HttpClientRequest request) {
       expect(result == 'true');  // The session cache may keep the session.
       return request.close();
     }, onError: (e) {
       expect(e is HandshakeException || e is SocketException);
-    }));
+    });
 
-  return Future.wait(testFutures).then((_) => client.close());
+  client.close();
 }
 
 void main(List<String> args) {
   SecureSocket.initialize();
   int port = int.parse(args[0]);
   runHttpClient(port, args[1])
     .then((_) => print('SUCCESS'));
 }