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

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.
 
 library test.utils;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:math' as math;
 
 import 'package:crypto/crypto.dart';
 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';
 
+/// 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());
@@ skipping 47 matching lines @@
 ///
 /// Many exceptions include the exception class name at the beginning of their
 /// [toString], so we remove that if it exists.
 String getErrorMessage(error) =>
   error.toString().replaceFirst(_exceptionPrefix, '');
 
 /// Indent each line in [str] by two spaces.
 String indent(String str) =>
     str.replaceAll(new RegExp("^", multiLine: true), "  ");
 
+/// Returns a sentence fragment listing the elements of [iter].
+///
+/// This converts each element of [iter] to a string and separates them with
+/// commas and/or "and" where appropriate.
+String toSentence(Iterable iter) {
+  if (iter.length == 1) return iter.first.toString();
+  var result = iter.take(iter.length - 1).join(", ");
+  if (iter.length > 2) result += ",";
+  return "$result and ${iter.last}";
+}
+
+/// Wraps [text] so that it fits within [lineLength], which defaults to 100
+/// characters.
+///
+/// This preserves existing newlines and doesn't consider terminal color escapes
+/// part of a word's length.
+String wordWrap(String text, {int lineLength}) {
+  if (lineLength == null) lineLength = _lineLength;
+  return text.split("\n").map((originalLine) {
+    var buffer = new StringBuffer();
+    var lengthSoFar = 0;
+    for (var word in originalLine.split(" ")) {
+      var wordLength = withoutColors(word).length;
+      if (wordLength > lineLength) {
+        if (lengthSoFar != 0) buffer.writeln();
+        buffer.writeln(word);
+      } else if (lengthSoFar == 0) {
+        buffer.write(word);
+        lengthSoFar = wordLength;
+      } else if (lengthSoFar + 1 + wordLength > lineLength) {
+        buffer.writeln();
+        buffer.write(word);
+        lengthSoFar = wordLength;
+      } else {
+        buffer.write(" $word");
+        lengthSoFar += 1 + wordLength;
+      }
+    }
+    return buffer.toString();
+  }).join("\n");
+}
+
 /// A regular expression matching terminal color codes.
 final _colorCode = new RegExp('\u001b\\[[0-9;]+m');
 
 /// Returns [str] without any color codes.
 String withoutColors(String str) => str.replaceAll(_colorCode, '');
 
 /// A regular expression matching the path to a temporary file used to start an
 /// isolate.
 ///
 /// These paths aren't relevant and are removed from stack traces.
@@ skipping 249 matching lines @@
   }
 }
 
 /// 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;
   };
 }