I would caution against using CVS unless you can guarantee getting and printing/saving the results before you leave the US. We made this mistake recently and departed the US while still waiting for the test messages with the results. When the text finally arrived, it included a link to the results at CVS.com. However, the CVS.com website is not accessible outside of the USA! We had to test again at EIS on arrival at a cost of $50 and some delay.

CVS promoted these test as being valid for most travel but I can find no warning about inability to access the results if you are travelling outside the US.