### Question:
ClientGenericOrder implements ClientOrder, ClientFieldReference { @XmlElement(name = "aggregation") public Boolean isAggregation() { return isAggregationLevel == IS_AGGREGATION_DEFAULT ? null : isAggregationLevel; } ClientGenericOrder();  ClientGenericOrder(ClientGenericOrder sorting); @Override ClientGenericOrder deepClone(); @Override Boolean isAscending(); ClientGenericOrder setAscending(Boolean isAscending); @XmlElement(name = "fieldRef") String getFieldReference(); ClientGenericOrder setFieldReference(String fieldReference); @XmlTransient Boolean isAggregationLevel(); @XmlElement(name = "aggregation") Boolean isAggregation(); ClientGenericOrder setAggregation(Boolean aggregationLevel); @Override boolean equals(Object o); @Override int hashCode(); @Override String toString(); static final Boolean IS_AGGREGATION_DEFAULT; }### Answer:
@Test public void isAggregation_default() { ClientGenericOrder instance = new ClientGenericOrder(); assertNull(instance.isAggregation()); }