pkg/shelf: handle errors when parsing HttpRequest in shelf_io

pkg/shelf/test/shelf_io_test.dart

 // Copyright (c) 2014, 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 shelf_io_test;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
@@ skipping 233 matching lines @@
       }, 'localhost', 0).then((server) {
         return http.get('http://localhost:${server.port}').then((response) {
           expect(response.statusCode, HttpStatus.OK);
           expect(response.body, 'Hello from /');
           server.close();
         });
       });
     });
   });
 
+  test('a bad HTTP request results in a 500 response', () {
+    var socket;
+
+    _scheduleServer(syncHandler);
+
+    schedule(() {
+      return Socket.connect('localhost', _serverPort).then((value) {
+        socket = value;
+
+        currentSchedule.onComplete.schedule(() {
+          return socket.close();
+        }, 'close the socket');
+      });
+    });
+
+    schedule(() {
+      socket.write('GET / HTTP/1.1\r\n');
+      socket.write('Host: ^^super bad !@#host\r\n');
+      socket.write('\r\n');
+      return socket.close();
+    });
+
+    schedule(() {
+      return UTF8.decodeStream(socket).then((value) {
+        expect(value, contains('500 Internal Server Error'));
+      });
+    });
+  });
+
   group('date header', () {
     test('is sent by default', () {
       _scheduleServer(syncHandler);
 
       // Update beforeRequest to be one second earlier. HTTP dates only have
       // second-level granularity and the request will likely take less than a
       // second.
       var beforeRequest = new DateTime.now().subtract(new Duration(seconds: 1));
 
       return _scheduleGet().then((response) {
@@ skipping 71 matching lines @@
 
     var request = new http.Request('POST',
         Uri.parse('http://localhost:$_serverPort/'));
 
     if (headers != null) request.headers.addAll(headers);
     if (body != null) request.body = body;
 
     return request.send();
   });
 }