@Test
public void average() {

    Aggregation<Double> avg = Aggregations.avg();
    avg.aggregate(null);
    avg.aggregate(1D);
    avg.aggregate(2D);
    avg.aggregate(3D);
    avg.aggregate(4D);
    double aggregated = avg.getAggregated();
    Assert.assertEquals(2.5D, aggregated, DELTA);
    Assert.assertEquals("avg", avg.getIdentifier());
    avg.reset();
}