This was on visitJamaica.com this morning:

IMPORTANT
Beginning August 20, 2020, all persons visiting Jamaica aged 12 and over who are residents of the United States of America (USA), Brazil, Dominican Republic or Mexico, will be required to obtain a COVID-19 RT-PCR test within 10 days prior to their intended date of travel. The test result must be uploaded as part of the Travel Authorization application process.

Until the above mentioned measures takes effect on August 20, the similar requirement for residents of Arizona, Florida, New York and Texas in the USA, will continue to apply.

The test should be performed at a medical laboratory that is accredited by the relevant national health authorities. For the United States of America, the medical laboratory should be accredited by the College of American Pathologists (CAP).