public void testInterfaceProxySerializable() throws Exception {
    SerializableTester.reserializeAndAssert(tester.instantiate(HasAnInterface.class));
  }

  public void testReturnValuesFromAnotherPackageIgnoredForNullTests() throws Exception {
    new ClassSanityTester().forAllPublicStaticMethods(JdkObjectFactory.class).testNulls();
  }

  /** String doesn't check nulls as we expect. But the framework should ignore. */