/** check {@link ImmutableTimeStampedCache#emptyCache()}. */
  @Test
  public void testEmptyCache() {
    // setup
    cache = ImmutableTimeStampedCache.emptyCache();

    // actions + verify
    try {
      cache.getNeighbors(date);
      Assert.fail("Expected Exception");
    } catch (TimeStampedCacheException e) {
      // expected
    }
    try {
      cache.getEarliest();
      Assert.fail("Expected Exception");
    } catch (IllegalStateException e) {
      // expected
    }
    try {
      cache.getLatest();
      Assert.fail("Expected Exception");
    } catch (IllegalStateException e) {
      // expected
    }
    Assert.assertEquals(cache.getAll().size(), 0);
    Assert.assertEquals(cache.getNeighborsSize(), 0);
  }
 /** check {@link ImmutableTimeStampedCache#getLatest()} */
 @Test
 public void testGetLatest() {
   Assert.assertEquals(cache.getLatest(), data.get(data.size() - 1));
 }