Add corelib tests

test/codegen/corelib/date_time2_test.dart

Index: test/codegen/corelib/date_time2_test.dart
diff --git a/test/codegen/corelib/date_time2_test.dart b/test/codegen/corelib/date_time2_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..6a0bb87dae5258b3149232f6f1b6ec29f06e4a3f
--- /dev/null
+++ b/test/codegen/corelib/date_time2_test.dart
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+// 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.
+
+import "package:expect/expect.dart";
+
+// Dart test program for DateTime's hashCode.
+
+main() {
+  var d = DateTime.parse("2000-01-01T00:00:00Z");
+  var d2 = DateTime.parse("2000-01-01T00:00:01Z");
+  // There is no guarantee that the hashcode for these two dates is different,
+  // but in the worst case we will have to fix this test.
+  // The important test here is, that DateTime .
+  Expect.isFalse(d.hashCode == d2.hashCode);
+}