ThreadLocalStack { public T peek() { Deque<T> stack = stackLocal.get(); return stack != null ? stack.peekFirst() : null; }  T push(T item); T peek(); T pop(); T popOrError(); T get(); T getOrError(); void set(T item); void remove(); void with(T item, WithProcedure procedure);  }
@Test public void peek() { assertThat(stack.get(), equalTo(INITIAL_VALUE)); }