### Question:
StringStack implements Iterable<String> { public boolean add(String e) { block.add(e.getBytes(UTF_8)); start_byte.add(block.size()); return true; } 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 testAdd() { StringStack ss = new StringStack(); assertEquals(0, ss.size()); ss.add("moo"); assertEquals(1, ss.size()); assertFalse(ss.contains("erk")); assertTrue(ss.contains("moo")); ss.add("moo"); assertEquals(2, ss.size()); ss.add("erk"); assertEquals(3, ss.size()); assertTrue(ss.contains("erk")); assertTrue(ss.contains("moo")); }