Is there a test suite for Pi2/armv7 ?

I've got a couple of old-ish Pi2 v1.1 32 bit hosts. Both
have started to behave strangely, one having trouble booting
and the other reporting what could be thought of as "off by one"
errors that cause processes to report errors.

They're the first two Pi2s purchased, in 2015. They've been
powered on close to 24/7 since and I'm starting to wonder
if they're wearing out. I didn't think it possible, but I'm
running out of other ideas that make sense.

Is there a hardware test suite for the Raspberry Pi that can
identify faulty hardware? I know, this sounds a bit like the
halting problem, which is insoluble, but I think it's slightly
more tractable, maybe. Perhaps what I'm looking for is a kind
of fuzzing test, though fuzzing usually tests software error
handling and I'm looking for hardware errors (I think!).

Test suites for i386 PCs used to be common, especially for
memory. Something similar for the Pi2 would be a start.

Thanks for reading,

bob prohaska