Test

function checkSlot()
  if turtle.getItemCount(turtle.getSelectedSlot()) == 0 then
    selectNext()
    for i = 1, 15 do
      if turtle.getItemCount(turtle.getSelectedSlot()) > 0 then
        return true
      end
      selectNext()
    end
    return false
  end
  return true
end

function selectNext()
  if turtle.getSelectedSlot() == 16 then
    turtle.select(1)
  else
    turtle.select(turtle.getSelectedSlot() + 1)
  end
end

turtle.select(1)
while true do
  if not checkSlot() then break end
  turtle.drop(1)
end

print("Out of blocks. Program Terminating.")