They would be testing them individually as they were packaged. While you can't be certain of the extent of the testing unless you're involved, at the very least they're testing to sort out parts from bad dies from near the edge of the wafer (perhaps only 1 or 2 of the engines functional) and for major faults like Vcc shorted to GND.
How extensive the testing is per chip will depend on the testbeds and simulations that OrSoc provided the packager. They're doing at least gross electrical testing at a minimum. They probably are not going so far as binning parts with 4 engines showing up as functional...
There was a concrete question at the KnC open day, if they will do any wafer level or chip level final tests. They clearly answered with no.
If this is still true, they are currently doing a blind packaging of all dies (including the completely bad dies from near the edge of wafers and dies with electrical shorts) and they will assemble all these chips to PCBs. The first time they will notice that there is something wrong with a single chip is when they try to hash with it assembled to a PCB.
This is probably the fastest way to get a chip hashing (because they save the time required for bringing up and debugging a production test environment). But it could be that they have to throw away a lot of fully assembled PCBs. Not optimal in terms of costs, but finally KnC’s problem.