synchronized void add(int splitCount) {
    int pos = count % history.length;
    history[pos] = splitCount;
    count += 1;
  }
@Test
  public void testTwoMoreThanFullHistory() {
    EnumerationHistory history = new EnumerationHistory(3);
    history.add(1);
    history.add(2);
    history.add(3);
    history.add(4);
    history.add(5);
    int[] expectedHistorySnapshot = {3, 4, 5};
    testHistory(history, expectedHistorySnapshot);
  }