Use YAML as the format for the pubspec file.

utils/tests/pub/pub_tests.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('pub_tests');
 
 #import('dart:io');
 
 #import('test_pub.dart');
 #import('../../../lib/unittest/unittest.dart');
@@ skipping 52 matching lines @@
 }
 
 updateCommand() {
   testPub('adds a dependent package',
     cache: [
       dir('foo', [
         file('foo.dart', 'main() => "foo";')
       ])
     ],
     app: dir('myapp', [
-      file('pubspec', 'foo')
+      file('pubspec', '- foo')

[Bob Nystrom, 2012/04/25 22:59:01]

Now that we have a real format, I would put the dependencies under a
dependencies key like:

dependencies:
- foo
- bar

(I may have the YAML wrong here.)

[nweiz, 2012/04/25 23:05:14]

Done.

     ]),
     args: ['update'],
     expectedPackageDir: [
       dir('foo', [
         file('foo.dart', 'main() => "foo";')
       ])
     ],
     output: '');
 
   testPub('adds a transitively dependent package',
     cache: [
       dir('foo', [
         file('foo.dart', 'main() => "foo";'),
-        file('pubspec', 'bar')
+        file('pubspec', '- bar')
       ]),
       dir('bar', [
         file('bar.dart', 'main() => "bar";'),
       ])
     ],
     app: dir('myapp', [
-      file('pubspec', 'foo')
+      file('pubspec', '- foo')
     ]),
     args: ['update'],
     expectedPackageDir: [
       dir('foo', [
         file('foo.dart', 'main() => "foo";')
       ]),
       dir('bar', [
         file('bar.dart', 'main() => "bar";'),
       ])
     ],
     output: '');
 }
 
 versionCommand() {
   testPub('displays the current version',
     args: ['version'],
     output: '''
     Pub 0.0.0
     ''');
 }