Which companies perform in-house sleep studies?

I understand that some companies will cover the expense of a sleep study and if necessary, a CPAP machine. Of course, it comes out of the driver's paycheck (no freebies!) but that's to be expected. I've read that other companies want the drivers to arrive or return with a sleep study in-hand. In your experience, which companies provide in-house sleep studies? Thank you!!

 

That would be great, but I don't know which companies have great insurance. Research can only tell me so much. So far, I've only found (1) company that offers in-house studies, which would expedite the process if I'm tagged.