Add test for reusing the port of a server socket, after the server's close future is completed.

tests/standalone/io/http_reuse_server_port_test.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.
+//
+// VMOptions=
+// VMOptions=--short_socket_read
+// VMOptions=--short_socket_write
+// VMOptions=--short_socket_read --short_socket_write
+
+import "package:expect/expect.dart";
+import 'dart:async';
+import 'dart:io';
+import 'dart:isolate';
+
+Future<int> runServer(int port, int connections, bool clean) {
+  var completer = new Completer();
+  HttpServer.bind("127.0.0.1", port).then((server) {
+    int i = 0;
+    server.listen((request) {
+      request.pipe(request.response);
+      i++;
+      if (!clean && i == 10) {
+        int port = server.port;
+        server.close().then((_) => completer.complete(port));
+      }
+    });
+
+    Future.wait(new List.generate(connections, (_) {
+      var client = new HttpClient();
+      return client.get("127.0.0.1", server.port, "/")
+          .then((request) => request.close())
+          .then((response) => response.drain())
+          .catchError((e) { if (clean) throw e; });
+    })).then((_) {
+      if (clean) {
+        int port = server.port;
+        server.close().then((_) => completer.complete(port));
+      }
+    });
+  });
+  return completer.future;
+}
+
+
+void testReusePort() {
+  var keepAlive = new ReceivePort();
+  runServer(0, 10, true).then((int port) {
+    // Stress test the port reusing it 10 times.
+    Future.forEach(new List(10), (_) {
+      return runServer(port, 10, true);
+    }).then((_) {
+      keepAlive.close();
+    });
+  });
+}
+
+
+void testUncleanReusePort() {
+  var keepAlive = new ReceivePort();
+  runServer(0, 10, false).then((int port) {
+    // Stress test the port reusing it 10 times.
+    Future.forEach(new List(10), (_) {
+      return runServer(port, 10, false);
+    }).then((_) {
+      keepAlive.close();
+    });
+  });
+}
+
+
+void main() {
+  testReusePort();
+  testUncleanReusePort();
+}