### Question:
IntSinglyLinkedList implements Serializable, Iterable<Integer> { public void clear() { head = tail = null; size = 0; } IntSinglyLinkedList(); int size(); boolean contains(int item); void addLast(int item); void addFirst(int item); boolean isEmpty(); void clear(); int pop(); int peek(); void push(int item); int dequeue(); int getFirst(); void enqueue(int item); int[] toArray(); Integer[] toObjArray(); @Override String toString(); @Override boolean equals(Object other); @Override int hashCode(); @Override IntListIterator iterator();  }### Answer:
@Test public void testClear() { IntSinglyLinkedList list = new IntSinglyLinkedList(); for(int i = 0; i < 5; i++) { list.enqueue(i); } list.clear(); assertTrue(list.isEmpty()); }