temsAtEnd(1)" data-testid="add-1">+1</button>
  <button click.trigger="addItemsAtEnd(-1)" data-testid="remove-1">-1</button>
  <button click.trigger="addItemsAtEnd(10)" data-testid="add-10">+10</button>
  <button click.trigger="addItemsAtEnd(-10)" data-testid="remove-10">-10</button>
  <button click.trigger="addItemsAtEnd(100)" data-testid="add-100">+100</button>
  <button click.trigger="addItemsAtEnd(-100)" data-testid="remove-100">-100</button>
  <button click.trigger="addItemsAtEnd(-475)" data-testid="re