Add a --pause-after-load flag for debugging.

lib/src/util/io.dart

 // Copyright (c) 2015, 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 test.util.io;
 
 import 'dart:async';
+import 'dart:convert';
 import 'dart:io';
 import 'dart:mirrors';
 
+import 'package:async/async.dart';
 import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 
 import '../backend/operating_system.dart';
 import '../runner/application_exception.dart';
+import '../utils.dart';
 
 /// The ASCII code for a newline character.
 const _newline = 0xA;
 
 /// The ASCII code for a carriage return character.
 const _carriageReturn = 0xD;
 
 /// The root directory of the Dart SDK.
 final String sdkDir = (() {
   // TODO(kevmoo): work-around for accessing the SDK root dartbug.com/16994
@@ skipping 13 matching lines @@
 
 /// Returns the current operating system.
 final OperatingSystem currentOS = (() {
   var name = Platform.operatingSystem;
   var os = OperatingSystem.findByIoName(name);
   if (os != null) return os;
 
   throw new UnsupportedError('Unsupported operating system "$name".');
 })();
 
+/// A queue of lines of standard input.
+final stdinLines = new StreamQueue(
+    UTF8.decoder.fuse(const LineSplitter()).bind(stdin));
+
 /// The root directory below which to nest temporary directories created by the
 /// test runner.
 ///
 /// This is configurable so that the test code can validate that the runner
 /// cleans up after itself fully.
 final _tempDir = Platform.environment.containsKey("_UNITTEST_TEMP_DIR")
     ? Platform.environment["_UNITTEST_TEMP_DIR"]
     : Directory.systemTemp.path;
 
 /// The path to the `lib` directory of the `test` package.
@@ skipping 65 matching lines @@
     var previous;
     return list.reversed.where((byte) {
       if (byte == 0) return false;
       if (byte == _carriageReturn && previous == _newline) return false;
       previous = byte;
       return true;
     }).toList().reversed.toList();
   });
 }
 
+/// Print a warning containing [message].
+///
+/// This automatically wraps lines if they get too long. If [color] is passed,
+/// it controls whether the warning header is color; otherwise, it defaults to
+/// [canUseSpecialChars].
+void warn(String message, {bool color}) {
+  if (color == null) color = canUseSpecialChars;
+  var header = color
+      ? "\u001b[33mWarning:\u001b[0m"
+      : "Warning:";
+  stderr.writeln(wordWrap("$header $message\n"));
+}
+
 /// Creates a URL string for [address]:[port].
 ///
 /// Handles properly formatting IPv6 addresses.
 Uri baseUrlForAddress(InternetAddress address, int port) {
   if (address.isLoopback) {
     return new Uri(scheme: "http", host: "localhost", port: port);
   }
 
   // IPv6 addresses in URLs need to be enclosed in square brackets to avoid
   // URL ambiguity with the ":" in the address.
@@ skipping 24 matching lines @@
 /// returned.
 String libraryPath(Symbol libraryName, {String packageRoot}) {
   var lib = currentMirrorSystem().findLibrary(libraryName);
   if (lib.uri.scheme != 'package') return p.fromUri(lib.uri);
 
   // TODO(nweiz): is there a way to avoid assuming this is being run next to a
   // packages directory?.
   if (packageRoot == null) packageRoot = p.absolute('packages');
   return p.join(packageRoot, p.fromUri(lib.uri.path));
 }