Update tests for pkg/http for new library

pkg/http/test/http_test.dart

-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// 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.
 
 library http_test;
 
 import 'dart:io';
 
 import 'package:unittest/unittest.dart';
 import 'package:http/http.dart' as http;
 import 'utils.dart';
@@ skipping 145 matching lines @@
         'path': '/',
         'headers': {
           'content-length': ['0'],
           'x-random-header': ['Value'],
           'x-other-header': ['Other Value']
         },
       }))));
     });
 
     test('read throws an error for a 4** status code', () {
-      http.read(serverUrl.resolve('/error')).catchError(expectAsync1((e) {
-        expect(true, e.error is HttpException);
-      }));
+      http.read(serverUrl.resolve('/error'))
+          .then((_) { throw "Error expected for readBytes"; })
+          .catchError(expectAsync1((e) { }), test: (e) => e is HttpException);
     });
 
     test('readBytes', () {
       var future = http.readBytes(serverUrl, headers: {
         'X-Random-Header': 'Value',
         'X-Other-Header': 'Other Value'
       }).then(expectAsync1((bytes) => new String.fromCharCodes(bytes)));
 
       expect(future, completion(parse(equals({
         'method': 'GET',
         'path': '/',
         'headers': {
           'content-length': ['0'],
           'x-random-header': ['Value'],
           'x-other-header': ['Other Value']
         },
       }))));
     });
 
     test('readBytes throws an error for a 4** status code', () {
-      http.readBytes(serverUrl.resolve('/error')).catchError(expectAsync1((e) {
-        expect(true, e.error is HttpException);
-      }));
+        http.readBytes(serverUrl.resolve('/error'))
+            .then((_) { throw "Error expected for readBytes"; })
+            .catchError(expectAsync1((e) { }), test: (e) => e is HttpException);
     });
   });
 }