Use "package:" imports for pub.

test/lish/does_not_publish_if_private_with_server_arg_test.dart

 // Copyright (c) 2014, 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.
 
+import 'package:pub/src/exit_codes.dart' as exit_codes;
 import 'package:scheduled_test/scheduled_test.dart';
 
-import '../../lib/src/exit_codes.dart' as exit_codes;
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 
 main() {
   initConfig();
   integration('does not publish if the package is private even if a server '
       'argument is provided', () {
     var pkg = packageMap("test_pkg", "1.0.0");
     pkg["publish_to"] = "none";
     d.dir(appPath, [d.pubspec(pkg)]).create();
 
     schedulePub(args: ["lish", "--server", "http://example.com"],
         error: startsWith("A private package cannot be published."),
         exitCode: exit_codes.DATA);
   });
 }