Use "package:" imports for pub.

test/validator/pubspec_field_test.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.
 
+import 'package:pub/src/entrypoint.dart';
+import 'package:pub/src/validator.dart';
+import 'package:pub/src/validator/pubspec_field.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
-import '../../lib/src/entrypoint.dart';
-import '../../lib/src/validator.dart';
-import '../../lib/src/validator/pubspec_field.dart';
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import 'utils.dart';
 
 Validator pubspecField(Entrypoint entrypoint) =>
   new PubspecFieldValidator(entrypoint);
 
 main() {
   initConfig();
 
@@ skipping 145 matching lines @@
 
     integration('has a non-HTTP documentation URL', () {
       var pkg = packageMap("test_pkg", "1.0.0");
       pkg["documentation"] = "file:///foo/bar";
       d.dir(appPath, [d.pubspec(pkg)]).create();
 
       expectValidationError(pubspecField);
     });
   });
 }