### Question:
CircularArraySequence implements Sequence { @Override public boolean isEmpty() { if (fillCount>0){ return false; } return true; } CircularArraySequence(int size);  CircularArraySequence(CircularArraySequence<T> seq); @Override Object head(); @Override Object last(); @Override Sequence front(); @Override Sequence tail(); @Override Sequence<T> concat(Sequence seq); @Override boolean contains(Sequence subseq); @Override boolean contains(Object element); @Override void append(Object element); @Override void prepend(Object element); @Override boolean isEmpty(); @Override Object peekHead(); @Override Object peekLast(); @Override boolean equals(Sequence seq); @Override int length(); @Override Iterator<T> iterator(); String toString();  }### Answer:
@Test public void testIsEmpty() { assertTrue(seq.isEmpty()); seq.append("A"); assertFalse(seq.isEmpty()); seq.last(); assertTrue(seq.isEmpty()); }