Late but I found a power supply tester on amazon that looks pretty handyhttps://www.amazon.com/CRJ-24-Pin-Switch-Jumper-Sleeved/dp/B01MSY4966/ref=sr_1_17?keywords=power+supply+tester&qid=1576294227&sr=8-17
I've got an older system by today's standards that still runs the game well by my standards.
Although that's not expensive, the paper clip does the same for free.'I have one of these:https://www.amazon.com/Comidox-Computer-Supply-Tester-Automatic/dp/B07J9LRC6T/ref=sr_1_11?keywords=power+supply+tester&qid=1576335019&sr=8-11. It's a tad better than just a switch/clip, it also tells the voltages and Power Good time. Basically it's a dedicated multimeter. What's common with these cheap testers is that they don't tell how the PSU works loaded.
That's Dang near identical to mine...but I paid nearly $30 around 9 or 10 years ago....They do come in very handy