Fix analyzer hints and warnings in test/.

test/validator/pubspec_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.dart';
-import 'package:scheduled_test/scheduled_test.dart';
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import 'utils.dart';
 
 main() {
   integration('should consider a package valid if it has a pubspec', () {
     d.validPackage.create();
 
     expectNoValidationError((entrypoint) => new PubspecValidator(entrypoint));
   });
 
   integration('should consider a package invalid if it has a .gitignored '
       'pubspec', () {
     var repo = d.git(appPath, [d.file(".gitignore", "pubspec.yaml")]);
     d.validPackage.create();
     repo.create();
 
     expectValidationError((entrypoint) => new PubspecValidator(entrypoint));
   });
 }