It's possible the chip is being powered through the clamping diodes on the IO pins, but that's pretty irrelevant as it doesn't make sense to "test" something like this. You really should wire it up properly or not at all.
It's possible the chip is being powered through the clamping diodes on the IO pins, but that's pretty irrelevant as it doesn't make sense to "test" something like this. You really should wire it up properly or not at all.