Use the VM to detect when a precompiled executable is out-of-date.

sdk/lib/_internal/pub/test/descriptor.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.
 
 /// Pub-specific scheduled_test descriptors.
 library descriptor;
 
 import 'package:oauth2/oauth2.dart' as oauth2;
 import 'package:scheduled_test/scheduled_server.dart';
 import 'package:scheduled_test/descriptor.dart';
 
+import '../lib/src/io.dart';
 import '../lib/src/utils.dart';
 import 'descriptor/git.dart';
 import 'descriptor/tar.dart';
 import 'test_pub.dart';
 
 export 'package:scheduled_test/descriptor.dart';
 export 'descriptor/git.dart';
 export 'descriptor/tar.dart';
 
 /// Creates a new [GitRepoDescriptor] with [name] and [contents].
 GitRepoDescriptor git(String name, [Iterable<Descriptor> contents]) =>
     new GitRepoDescriptor(name, contents == null ? <Descriptor>[] : contents);
 
 /// Creates a new [TarRepoDescriptor] with [name] and [contents].
 TarFileDescriptor tar(String name, [Iterable<Descriptor> contents]) =>
     new TarFileDescriptor(name, contents == null ? <Descriptor>[] : contents);
 
 /// Describes a package that passes all validation.
 Descriptor get validPackage => dir(appPath, [
   libPubspec("test_pkg", "1.0.0"),
   file("LICENSE", "Eh, do what you want."),
   dir("lib", [
     file("test_pkg.dart", "int i = 1;")
   ])
 ]);
 
+/// Returns a descriptor of a snapshot that can't be run by the current VM.
+///
+/// This snapshot was generated by the VM on r39611, the revision immediately
+/// before snapshot versioning was added.
+FileDescriptor outOfDateSnapshot(String name) =>
+    binaryFile(name, readBinaryFile(testAssetPath('out-of-date.snapshot')));
+
 /// Describes a file named `pubspec.yaml` with the given YAML-serialized
 /// [contents], which should be a serializable object.
 ///
 /// [contents] may contain [Future]s that resolve to serializable objects,
 /// which may in turn contain [Future]s recursively.
 Descriptor pubspec(Map contents) {
   return async(awaitObject(contents).then((resolvedContents) =>
       file("pubspec.yaml", yaml(resolvedContents))));
 }
 
@@ skipping 119 matching lines @@
           ['https://www.googleapis.com/auth/userinfo.email'],
           expiration).toJson())
     ]);
   }));
 }
 
 /// Describes the application directory, containing only a pubspec specifying
 /// the given [dependencies].
 DirectoryDescriptor appDir([Map dependencies]) =>
   dir(appPath, [appPubspec(dependencies)]);