### Question:
StringStack implements Iterable<String> { public void clear() { start_byte.clear(); start_byte.add(0); block.clear(); } StringStack(String... xs);  StringStack(Iterable<String> xs); int size(); boolean isEmpty(); boolean contains(String o); boolean add(String e); void clear(); String get(int index); int indexOf(String o); Iterator<String> iterator();  }### Answer:
@Test public void testClear() { StringStack ss = new StringStack("moo"); ss.clear(); assertEquals(0, ss.size()); assertFalse(ss.contains("moo")); }