diff --git a/sdk/lib/io/string_stream.dart b/sdk/lib/io/string_stream.dart
index 3140a3623f4..d3a698446cd 100644
--- a/sdk/lib/io/string_stream.dart
+++ b/sdk/lib/io/string_stream.dart
@@ -11,6 +11,8 @@ abstract class _StringDecoder {
   // is transfered to the decoder and the caller most not modify it any more.
   int write(List<int> buffer);
 
+  void done();
+
   // Returns whether any decoded data is available.
   bool get isEmpty;
 
@@ -88,6 +90,8 @@ abstract class _StringDecoderBase implements _StringDecoder {
     return buffer.length;
   }
 
+  void done() { }
+
   bool get isEmpty => _result.isEmpty;
 
   int get lineBreaks => _lineBreaks;
@@ -185,6 +189,12 @@ class _UTF8Decoder extends _StringDecoderBase {
   static const kMaxCodePoint = 0x10FFFF;
   static const kReplacementCodePoint = 0x3f;
 
+  void done() {
+    if (!_bufferList.isEmpty) {
+      _reportError(new DecoderException("Illegal UTF-8"));
+    }
+  }
+
   void _reportError(error) {
     if (onError != null) {
       onError(error);
@@ -217,7 +227,7 @@ class _UTF8Decoder extends _StringDecoderBase {
         value = value & 0x01;
         additionalBytes = 5;
       } else {
-        _reportError(new DecoderException("Illegal UTF-8"));
+        return _reportError(new DecoderException("Illegal UTF-8"));
       }
       // Check if there are enough bytes to decode the character. Otherwise
       // return false.
@@ -229,7 +239,7 @@ class _UTF8Decoder extends _StringDecoderBase {
       for (int i = 0; i < additionalBytes; i++) {
         int byte = _bufferList.next();
         if ((byte & 0xc0) != 0x80) {
-          _reportError(new DecoderException("Illegal UTF-8"));
+          return _reportError(new DecoderException("Illegal UTF-8"));
         }
         value = value << 6 | (byte & 0x3F);
       }
@@ -477,6 +487,7 @@ class _StringInputStream implements StringInputStream {
 
   void _onClosed() {
     _inputClosed = true;
+    _decoder.done();
     if (_decoder.isEmpty && _clientCloseHandler !=  null) {
       _clientCloseHandler();
     } else {
diff --git a/tests/standalone/io/string_decoder_test.dart b/tests/standalone/io/string_decoder_test.dart
index d79bf8d7bf3..879cf8c0c57 100644
--- a/tests/standalone/io/string_decoder_test.dart
+++ b/tests/standalone/io/string_decoder_test.dart
@@ -1,38 +1,50 @@
-// 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.
 
-part '../../../sdk/lib/io/buffer_list.dart';
-part '../../../sdk/lib/io/input_stream.dart';
-part '../../../sdk/lib/io/string_stream.dart';
+import "dart:io";
 
 void test() {
   // Code point U+10FFFF is the largest code point supported by Dart.
-  var decoder = _StringDecoders.decoder(Encoding.UTF_8);
-  decoder.write([0xf0, 0x90, 0x80, 0x80]);  // U+10000
-  decoder.write([0xf4, 0x8f, 0xbf, 0xbf]);  // U+10FFFF
-  decoder.write([0xf4, 0x90, 0x80, 0x80]);  // U+110000
-  decoder.write([0xfa, 0x80, 0x80, 0x80, 0x80]);  //  U+2000000
-  decoder.write([0xfd, 0x80, 0x80, 0x80, 0x80, 0x80]);  // U+40000000
+  //var decoder = _StringDecoders.decoder(Encoding.UTF_8);
+  ListInputStream lis = new ListInputStream();
+  lis.write([0xf0, 0x90, 0x80, 0x80]);  // U+10000
+  lis.write([0xf4, 0x8f, 0xbf, 0xbf]);  // U+10FFFF
+  lis.write([0xf4, 0x90, 0x80, 0x80]);  // U+110000
+  lis.write([0xfa, 0x80, 0x80, 0x80, 0x80]);  //  U+2000000
+  lis.write([0xfd, 0x80, 0x80, 0x80, 0x80, 0x80]);  // U+40000000
+  lis.markEndOfStream();
 
-  var decoded = decoder.decoded();
-  Expect.equals(7, decoded.length);
+  var sis = new StringInputStream(lis);
+  sis.onData = () {
+    var decoded = sis.read();
+    Expect.equals(7, decoded.length);
 
-  var replacementChar = '?'.charCodeAt(0);
-  Expect.equals(0xd800, decoded.charCodeAt(0));
-  Expect.equals(0xdc00, decoded.charCodeAt(1));
-  Expect.equals(0xdbff, decoded.charCodeAt(2));
-  Expect.equals(0xdfff, decoded.charCodeAt(3));
-  Expect.equals(replacementChar, decoded.charCodeAt(4));
-  Expect.equals(replacementChar, decoded.charCodeAt(5));
-  Expect.equals(replacementChar, decoded.charCodeAt(6));
+    var replacementChar = '?'.charCodeAt(0);
+    Expect.equals(0xd800, decoded.charCodeAt(0));
+    Expect.equals(0xdc00, decoded.charCodeAt(1));
+    Expect.equals(0xdbff, decoded.charCodeAt(2));
+    Expect.equals(0xdfff, decoded.charCodeAt(3));
+    Expect.equals(replacementChar, decoded.charCodeAt(4));
+    Expect.equals(replacementChar, decoded.charCodeAt(5));
+    Expect.equals(replacementChar, decoded.charCodeAt(6));
+  };
 }
 
 void testInvalid() {
-  var decoder = _StringDecoders.decoder(Encoding.UTF_8);
-  Expect.throws(() => decoder.write([0x80]));
-  Expect.throws(() => decoder.write([0xff]));
-  Expect.throws(() => decoder.write([0xf0, 0xc0]));
+  void invalid(var bytes) {
+    ListInputStream lis = new ListInputStream();
+    lis.write(bytes);
+    lis.markEndOfStream();
+    var sis = new StringInputStream(lis);
+    sis.onData = () { throw "onData not expected"; };
+    sis.onError = (e) { Expect.isTrue(e is DecoderException); };
+    sis.onClosed = () { throw "onClosed not expected"; };
+  }
+
+  invalid([0x80]);
+  invalid([0xff]);
+  invalid([0xf0, 0xc0]);
 }
 
 void main() {