Allow Suites to be added to an Engine over time.

test/io.dart

Index: test/io.dart
diff --git a/test/io.dart b/test/io.dart
index 5cf6ece29573b458aa8073ba304ccd358d52c601..a389ea04b625e3c147e395445b9c4aa5e79acc35 100644
--- a/test/io.dart
+++ b/test/io.dart
@@ -25,9 +25,6 @@ final String noSuchFileMessage = Platform.isWindows
     ? "The system cannot find the file specified."
     : "No such file or directory";
 
-/// A decoder that converts raw bytes to a line-by-line stream.
-final _lines = UTF8.decoder.fuse(const LineSplitter());
-
 /// A regular expression that matches the output of "pub serve".
 final _servingRegExp =
     new RegExp(r'^Serving myapp [a-z]+ on http://localhost:(\d+)$');
@@ -117,7 +114,7 @@ Future<Pair<Process, int>> startPubServe({List<String> args,
 
   var process = await startPub(allArgs,
       workingDirectory: workingDirectory, environment: environment);
-  var line = await _lines.bind(process.stdout)
+  var line = await lineSplitter.bind(process.stdout)
       .firstWhere(_servingRegExp.hasMatch);
   var match = _servingRegExp.firstMatch(line);