pkg/test: Resolve a number of analyzer warnings

lib/src/utils.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.
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:math' as math;
 import 'dart:typed_data';
 
 import 'package:async/async.dart' hide StreamQueue;
 import 'package:path/path.dart' as p;
 import 'package:shelf/shelf.dart' as shelf;
 import 'package:stack_trace/stack_trace.dart';
 
 import 'backend/operating_system.dart';
 import 'util/path_handler.dart';
 import 'util/stream_queue.dart';
 
 /// The maximum console line length.
 const _lineLength = 100;
 
 /// A typedef for a possibly-asynchronous function.
 ///
 /// The return type should only ever by [Future] or void.
 typedef AsyncFunction();
 
 /// A typedef for a zero-argument callback function.
 typedef void Callback();
 
-/// A converter that decodes bytes using UTF-8 and splits them on newlines.
-final lineSplitter = UTF8.decoder.fuse(const LineSplitter());
+/// A transformer that decodes bytes using UTF-8 and splits them on newlines.
+final lineSplitter = new StreamTransformer<List<int>, String>(
+    (stream, cancelOnError) => stream
+        .transform(UTF8.decoder)
+        .transform(const LineSplitter())
+        .listen(null, cancelOnError: cancelOnError));
 
 /// A regular expression to match the exception prefix that some exceptions'
 /// [Object.toString] values contain.
 final _exceptionPrefix = new RegExp(r'^([A-Z][a-zA-Z]*)?(Exception|Error): ');
 
 /// A regular expression matching a single vowel.
 final _vowel = new RegExp('[aeiou]');
 
 /// Directories that are specific to OS X.
 ///
@@ skipping 315 matching lines @@
   return BASE64.encode(data);
 }
 
 /// Returns middleware that nests all requests beneath the URL prefix [beneath].
 shelf.Middleware nestingMiddleware(String beneath) {
   return (handler) {
     var pathHandler = new PathHandler()..add(beneath, handler);
     return pathHandler.handler;
   };
 }