Add tests for reflecting on null and Null.

tests/lib/mirrors/null_test.dart

Index: tests/lib/mirrors/null_test.dart
===================================================================
--- tests/lib/mirrors/null_test.dart	(revision 0)
+++ tests/lib/mirrors/null_test.dart	(revision 0)
@@ -0,0 +1,31 @@
+// 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.
+
+library test.null_test;
+
+import 'dart:mirrors';
+
+import 'package:expect/expect.dart';
+
+main() {
+  InstanceMirror nullMirror = reflect(null);
+  Expect.isTrue(nullMirror.getField(const Symbol('hashCode')).reflectee is int);
+  Expect.equals('Null',
+                nullMirror.getField(const Symbol('runtimeType')).reflectee
+                .toString());
+  Expect.isTrue(nullMirror.invoke(const Symbol('=='), [null]).reflectee);
+  Expect.isFalse(nullMirror.invoke(const Symbol('=='), [new Object()])
+                 .reflectee);
+  Expect.equals('null',
+                nullMirror.invoke(const Symbol('toString'), []).reflectee);
+  Expect.throws(() => nullMirror.invoke(const Symbol('notDefined'), []),
+                (e) => e is NoSuchMethodError,
+                'noSuchMethod');
+
+  ClassMirror NullMirror = nullMirror.type;
+  Expect.equals(const Symbol('Null'), NullMirror.simpleName);
+  Expect.equals(const Symbol('Object'), NullMirror.superclass.simpleName);
+  Expect.equals(null, NullMirror.superclass.superclass);
+  Expect.equals(null, NullMirror.owner);  // Null belongs to no library.

[ahe, 2013/08/06 11:13:38]

Where is this specified?

+}