Coca-Cola is expected to report earnings Tuesday morning before the markets open, and the news could be good for investors. Strong demand for diet beverages in the U.S. continues. Never mind that the company raised prices during the summer, saying the cost of making the cans was going up due to aluminum tariffs. Earnings are expected to be strong and the look ahead is positive. Will the demand for drinks stay steady, even as currency questions loom and costs remain elevated as packaging issues brought on by the trade war linger?