@Override
  public boolean isTracked(String key) {
    return OpType.fromSymbol(key) != null;
  }
@Test
  public void testIsTracked() {
    assertFalse(statistics.isTracked(null));
    assertFalse(statistics.isTracked(NO_SUCH_OP));

    final Iterator<LongStatistic> iter = statistics.getLongStatistics();
    while (iter.hasNext()) {
      final LongStatistic longStatistic = iter.next();
      assertTrue(statistics.isTracked(longStatistic.getName()));
    }
  }