@Test
public void testWrapEmptyThrows() throws Exception {

  final PrimitiveSet<PrfSet> primitiveSet = PrimitiveSet.newPrimitiveSet(PrfSet.class);
  assertThrows(
      GeneralSecurityException.class,
      new ThrowingRunnable() {
        @Override
        public void run() throws Throwable {
          new PrfSetWrapper().wrap(primitiveSet);
        }
      });
}