Hi Nical,
Your eval board request has come through our internal channels, and we'll work on getting something to you following the break.
The state of the shift register cannot be read externally, so its state cannot be directly confirmed. The shift register data output pin is intended to be used in applications where two or more switches are cascaded, where the serial control output from one switch feeds into the serial input of the downstrream switch. The data in the shift register could be read by shifting it out, but this would reprogram the chip with the new data that is shifted in (which, of course, could be the same as the original data).
Best regards.
--Jonathan