Ensure that hashCode and runtimeType work on null.

tests/corelib/null_test.dart

Index: tests/corelib/null_test.dart
diff --git a/tests/corelib/null_test.dart b/tests/corelib/null_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..5815638445670609ddfaaf69221dd89bda1fb5ff
--- /dev/null
+++ b/tests/corelib/null_test.dart
@@ -0,0 +1,38 @@
+// 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.
+
+// Test that Null inherits properties from Object.
+
+main() {
+  var x;
+
+  Expect.isTrue(x is Object);
+  Expect.isTrue(x is Dynamic);
+  Expect.isTrue(x is! String);
+  Expect.isTrue(x is! int);
+
+  // These shouldn't throw.
+  x.runtimeType;
+  x.toString();
+  x.hashCode();
+
+  // operator== is inherited from Object. It's the same as identical.
+  // It's not really testable.
+  Expect.isTrue(identical(x, null));
+  Expect.isTrue(x == null);
+
+  // noSuchMethod must throw a NullPointerException.
+  Expect.throws(() => x.noSuchMethod(null, null),
+                (e) => e is NullPointerException);
+  Expect.throws(() => x.notThere(),
+                (e) => e is NullPointerException);
+
+  // Methods can be closurized and yields the same result.
+  var hc = x.hashCode;
+  Expect.equals(null.hashCode(), hc());
+  var ts = x.toString;
+  Expect.equals(null.toString(), ts());
+  var nsm = null.noSuchMethod;

[ngeoffray, 2012/09/27 11:00:29]

Maybe you can remove these two lines, so that dart2js passes this test, and add
another test?

[Lasse Reichstein Nielsen, 2012/09/27 11:25:13]

Done.

+  Expect.throws(() => nsm(null, null), (e) => e is NullPointerException);
+}