there are tons of threads already discussing this....there is a lot of good info in the thread below:

https://www.flyertalk.com/forum/indi...l-allowed.html

i've done this twice over the last couple of months....both times got my test done in nyc & told them i was due to travel within the next 72 hours....both times i got my result under 48 hours....

you can fill out the form even 24 hours prior to departure....both times i filled out the form on the last day & got my approval before i landed in del....