diff --git a/lib/src/utils.dart b/lib/src/utils.dart
index 65c4799..b626b1a 100644
--- a/lib/src/utils.dart
+++ b/lib/src/utils.dart
@@ -78,30 +78,20 @@
 Encoding encodingForCharset(
     String charset, [Encoding fallback = Encoding.ISO_8859_1]) {
   if (charset == null) return fallback;
-  var encoding = _encodingForCharset(charset);
+  var encoding = Encoding.fromName(charset);
   return encoding == null ? fallback : encoding;
 }
 
+
 /// Returns the [Encoding] that corresponds to [charset]. Throws a
 /// [FormatException] if no [Encoding] was found that corresponds to [charset].
 /// [charset] may not be null.
 Encoding requiredEncodingForCharset(String charset) {
-  var encoding = _encodingForCharset(charset);
+  var encoding = Encoding.fromName(charset);
   if (encoding != null) return encoding;
   throw new FormatException('Unsupported encoding "$charset".');
 }
 
-/// Returns the [Encoding] that corresponds to [charset]. Returns null if no
-/// [Encoding] was found that corresponds to [charset]. [charset] may not be
-/// null.
-Encoding _encodingForCharset(String charset) {
-  charset = charset.toLowerCase();
-  if (charset == 'ascii' || charset == 'us-ascii') return Encoding.ASCII;
-  if (charset == 'utf-8') return Encoding.UTF_8;
-  if (charset == 'iso-8859-1') return Encoding.ISO_8859_1;
-  return null;
-}
-
 /// Converts [bytes] into a [String] according to [encoding].
 String decodeString(List<int> bytes, Encoding encoding) {
   // TODO(nweiz): implement this once issue 6284 is fixed.
diff --git a/test/utils.dart b/test/utils.dart
index 8b404a5..a396097 100644
--- a/test/utils.dart
+++ b/test/utils.dart
@@ -1,4 +1,4 @@
-// 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.
 
@@ -57,9 +57,18 @@
       }
 
       new ByteStream(request).toBytes().then((requestBodyBytes) {
-        response.statusCode = 200;
-        response.headers.contentType = new ContentType("application", "json");
-      response.headers.set('single', 'value');
+        var outputEncoding;
+        var encodingName = request.queryParameters['response-encoding'];
+        if (encodingName != null) {
+          outputEncoding = requiredEncodingForCharset(encodingName);
+        } else {
+          outputEncoding = Encoding.ASCII;
+        }
+
+        response.headers.contentType =
+            new ContentType(
+                "application", "json", charset: outputEncoding.name);
+        response.headers.set('single', 'value');
 
         var requestBody;
         if (requestBodyBytes.isEmpty) {
@@ -86,17 +95,9 @@
           content['headers'][name] = values;
         });
 
-        var outputEncoding;
-        var encodingName = request.queryParameters['response-encoding'];
-        if (encodingName != null) {
-          outputEncoding = requiredEncodingForCharset(encodingName);
-        } else {
-          outputEncoding = Encoding.ASCII;
-        }
-
         var body = json.stringify(content);
         response.contentLength = body.length;
-        response.addString(body, outputEncoding);
+        response.write(body);
         response.close();
       });
     });