@Test(expectedExceptions = IllegalArgumentException.class)
 public void testInsufficientData() {
   final TimeSeries<Long, Double> subSeries =
       RANDOM.subSeries(RANDOM.getTimeAt(0), RANDOM.getTimeAt(3));
   SAMPLE_ACF.evaluate(
       new FastArrayLongDoubleTimeSeries(
           ENCODING, subSeries.timesArray(), subSeries.valuesArray()));
 }
 @Test(expectedExceptions = IllegalArgumentException.class)
 public void testInsufficientData() {
   final InstantDoubleTimeSeries subSeries =
       RANDOM.subSeries(RANDOM.getTimeAtIndex(0), RANDOM.getTimeAtIndex(3));
   LI_MCLEOD.evaluate(subSeries);
 }