DateTime is Comparable.

tests/corelib/date_time9_test.dart

Index: tests/corelib/date_time9_test.dart
diff --git a/tests/corelib/date_time9_test.dart b/tests/corelib/date_time9_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..40df97209f27d7f4d700f4ff926e0d348865c902
--- /dev/null
+++ b/tests/corelib/date_time9_test.dart
@@ -0,0 +1,42 @@
+// 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:expect/expect.dart";
+
+main() {
+  var dt = new DateTime.now();
+  Expect.isTrue(dt is Comparable);
+
+  var dt2 = new DateTime.fromMillisecondsSinceEpoch(100);
+  var dt3 = new DateTime.fromMillisecondsSinceEpoch(200, isUtc: true);
+  var dt3b = new DateTime.fromMillisecondsSinceEpoch(200);
+  var dt4 = new DateTime.fromMillisecondsSinceEpoch(300);
+  var dt5 = new DateTime.fromMillisecondsSinceEpoch(400, isUtc: true);
+  var dt5b = new DateTime.fromMillisecondsSinceEpoch(400);
+
+  Expect.isTrue(dt2.compareTo(dt2) == 0);
+  Expect.isTrue(dt3.compareTo(dt3) == 0);
+  Expect.isTrue(dt3b.compareTo(dt3b) == 0);
+  Expect.isTrue(dt4.compareTo(dt4) == 0);
+  Expect.isTrue(dt5.compareTo(dt5) == 0);
+  Expect.isTrue(dt5b.compareTo(dt5b) == 0);
+
+  // Time zones don't have any effect.
+  Expect.isTrue(dt3.compareTo(dt3b) == 0);
+  Expect.isTrue(dt5.compareTo(dt5b) == 0);
+
+  Expect.isTrue(dt2.compareTo(dt3) < 0);
+  Expect.isTrue(dt3.compareTo(dt4) < 0);
+  Expect.isTrue(dt4.compareTo(dt5) < 0);
+
+  Expect.isTrue(dt2.compareTo(dt3b) < 0);
+  Expect.isTrue(dt4.compareTo(dt5b) < 0);
+
+   Expect.isTrue(dt3.compareTo(dt2) > 0);
+  Expect.isTrue(dt4.compareTo(dt3) > 0);
+  Expect.isTrue(dt5.compareTo(dt4) > 0);
+
+  Expect.isTrue(dt3b.compareTo(dt2) > 0);
+  Expect.isTrue(dt5b.compareTo(dt4) > 0);
+}