pkg/args: a bunch of test cleanup

pkg/args/test/parse_test.dart

 // Copyright (c) 2012, 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 parse_test;
 
 import 'package:unittest/unittest.dart';
 import 'package:args/args.dart';
+import 'shared.dart';
 
-main() {
+void main() {
   group('ArgParser.parse()', () {
     test('does not destructively modify the argument list', () {
       var parser = new ArgParser();
       parser.addFlag('verbose');
 
       var args = ['--verbose'];
       var results = parser.parse(args);
       expect(args, equals(['--verbose']));
       expect(results['verbose'], isTrue);
     });
@@ skipping 393 matching lines @@
         var parser = new ArgParser();
         parser.addFlag('recurse', defaultsTo: false, abbr:'R');
         var results = parser.parse(['-R']);
         expect(results['recurse'], isTrue);
         expect(results.rest, [ ]);
         throwsFormat(parser, ['-r']);
       });
     });
   });
 }
-
-throwsIllegalArg(function) {
-  expect(function, throwsArgumentError);
-}
-
-throwsFormat(ArgParser parser, List<String> args) {
-  expect(() => parser.parse(args), throwsFormatException);
-}