Do we know @ETFbitcoin 's hash rate?
It looks like he used his GPU:
IIRC my GPU has speed about 200 Mh/s, so you should already mine at least a block within a month.
It also looks like my CPU mining is utterly useless

I'll give it another week, then I'll wipe it.
Indeed, that's a pity. @nullama may want to edit the original post / title and include the calculations I posted somehow.
It seems that CPUs are too weak even for difficulty=1, and even GPUs may struggle.
An old 1GH/s USB mining stick would take 4 whole seconds to mine a block and a 200MH/s graphics card takes 20 seconds. That's really stretching it, if you ask me, as ASIC miners will have a 20 second head start.
For ASICs owners like yourself: would it be possible to only turn it on when the difficulty is 1? Or use it for something else, and then switch to testnet mining when the last block was for instance 19 minutes and 50 seconds ago?
Yeah, that should definitely be possible. Although I don't think it's advised to heat cycle hardware a lot, so maybe it's worth modifying
cgminer to monitor the testnet blockchain and switch over whenever the last block approaches 20 min old. The ASIC doesn't care; it just hashes whatever it's given. But that way at least it stays hot and mines actually valuable BTC whenever the difficulty on testnet is higher than 1.
On the other hand, old / weaker ASICs make you such few sats per day that it's almost not worth the hassle to set this up. I'd just leave Compac F sticks on testnet for a day if I need tBTC and rest of the time on solo pool.