Add support for separators.

example/test_runner.dart

Index: example/test_runner.dart
diff --git a/example/test_runner.dart b/example/test_runner.dart
index 9480f417212a77ab21ecf764c394559af96f87f0..0d15e839970fcbb9630c4b59b339f8b53a0d1b52 100644
--- a/example/test_runner.dart
+++ b/example/test_runner.dart
@@ -14,11 +14,7 @@ import 'package:args/args.dart';
 main() {
   var parser = new ArgParser();
 
-  parser.addOption('mode',
-      abbr: 'm',
-      defaultsTo: 'debug',
-      help: 'Mode in which to run the tests',
-      allowed: ['all', 'debug', 'release']);
+  parser.addSeparator('===== Platform');
 
   parser.addOption('compiler',
       abbr: 'c',
@@ -80,6 +76,14 @@ main() {
       help: 'The operating system to run tests on',
       allowed: ['linux', 'macos', 'windows']);
 
+  parser.addSeparator('===== Runtime');
+
+  parser.addOption('mode',
+      abbr: 'm',
+      defaultsTo: 'debug',
+      help: 'Mode in which to run the tests',
+      allowed: ['all', 'debug', 'release']);
+
   parser.addFlag('checked',
       defaultsTo: false, help: 'Run tests in checked mode');
 
@@ -88,6 +92,24 @@ main() {
 
   parser.addOption('timeout', abbr: 't', help: 'Timeout in seconds');
 
+  parser.addOption('tasks',
+      abbr: 'j',
+      defaultsTo: Platform.numberOfProcessors.toString(),
+      help: 'The number of parallel tasks to run');
+
+  parser.addOption('shards',
+      defaultsTo: '1',
+      help: 'The number of instances that the tests will be sharded over');
+
+  parser.addOption('shard',
+      defaultsTo: '1',
+      help: 'The index of this instance when running in sharded mode');
+
+  parser.addFlag('valgrind',
+      defaultsTo: false, help: 'Run tests through valgrind');
+
+  parser.addSeparator('===== Output');
+
   parser.addOption('progress',
       abbr: 'p',
       defaultsTo: 'compact',
@@ -106,32 +128,24 @@ main() {
       defaultsTo: false,
       help: 'Print a summary report of the number of tests, by expectation');
 
-  parser.addOption('tasks',
-      abbr: 'j',
-      defaultsTo: Platform.numberOfProcessors.toString(),
-      help: 'The number of parallel tasks to run');
-
-  parser.addOption('shards',
-      defaultsTo: '1',
-      help: 'The number of instances that the tests will be sharded over');
-
-  parser.addOption('shard',
-      defaultsTo: '1',
-      help: 'The index of this instance when running in sharded mode');
-
   parser.addFlag('verbose',
       abbr: 'v', defaultsTo: false, help: 'Verbose output');
 
   parser.addFlag('list',
       defaultsTo: false, help: 'List tests only, do not run them');
 
+  parser.addFlag('time',
+      help: 'Print timing information after running tests', defaultsTo: false);
+
+  parser.addFlag('batch',
+      abbr: 'b', help: 'Run browser tests in batch mode', defaultsTo: true);
+
+  parser.addSeparator('===== Miscellaneous');
+
   parser.addFlag('keep-generated-tests',
       defaultsTo: false,
       help: 'Keep the generated files in the temporary directory');
 
-  parser.addFlag('valgrind',
-      defaultsTo: false, help: 'Run tests through valgrind');
-
   parser.addOption('special-command', help: """
 Special command support. Wraps the command line in
 a special command. The special command should contain
@@ -143,15 +157,9 @@ is 'dart file.dart' and you specify special command
 'python -u valgrind.py @ suffix' the final command will be
 'python -u valgrind.py dart file.dart suffix'""");
 
-  parser.addFlag('time',
-      help: 'Print timing information after running tests', defaultsTo: false);
-
   parser.addOption('dart', help: 'Path to dart executable');
   parser.addOption('drt', help: 'Path to content shell executable');
   parser.addOption('dartium', help: 'Path to Dartium Chrome executable');
 
-  parser.addFlag('batch',
-      abbr: 'b', help: 'Run browser tests in batch mode', defaultsTo: true);
-
   print(parser.usage);
 }