Add test annotations to package:expect

pkg/expect/lib/expect.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.
 
 /**
  * This library contains an Expect class with static methods that can be used
  * for simple unit-tests.
  */
 library expect;
 
@@ skipping 378 matching lines @@
 bool _identical(a, b) => identical(a, b);
 
 typedef bool _CheckExceptionFn(exception);
 typedef _Nullary();  // Expect.throws argument must be this type.
 
 class ExpectException implements Exception {
   ExpectException(this.message);
   String toString() => message;
   String message;
 }
+
+/// Annotation class for testing of dart2js. Use this as metadata on method

[sra1, 2015/02/13 20:37:38]

This is a strange place for these annotations.
Every test in the world can see them but they are specific to dart2js.

I would be much happier if these were in a separate library and shared with
sdk/lib/_internal/compiler/js_lib/annotations.dart

[floitsch, 2015/02/13 20:58:45]

:(
Didn't know/forgot about js_lib/annotations.dart.

We should merge them.

[floitsch, 2015/02/13 21:19:55]

Thinking more about it:
What would be the advantage of a separate library? The test still needs to run
in the VM. Importing dart2js-specific libraries into the test thus doesn't work.
In fact, given this constraint, we need to have the declarations visible to
every test. This makes a sharing pretty much impossible (or so complicated that
it isn't worth it).

However, we should align the naming of these two libraries.

+/// declarations to disable inlining of the annotated method.
+class NoInlining {
+  const NoInlining();
+}
+
+/// Annotation class for testing of dart2js. Use this as metadata on method
+/// declarations to make the type inferrer trust the parameter and return types,
+/// effectively asserting the runtime values will (at least) be subtypes of the
+/// annotated types.
+class TrustTypeAnnotations {
+  const TrustTypeAnnotations();
+}
+
+/// Annotation class for testing of dart2js. Use this as metadata on method
+/// declarations to disable closed world assumptions on parameters, effectively
+/// assuming that the runtime arguments could be any value.
+class AssumeDynamic {
+  const AssumeDynamic();
+}