/** A test for the clear method. */
  @Test
  public void testClear() {
    TimeSeries s1 = new TimeSeries("S1");
    s1.add(new Year(2009), 1.1);
    s1.add(new Year(2010), 2.2);

    assertEquals(2, s1.getItemCount());

    s1.clear();
    assertEquals(0, s1.getItemCount());
    assertTrue(Double.isNaN(s1.getMinY()));
    assertTrue(Double.isNaN(s1.getMaxY()));
  }