Comment by wtallis

If you have a host system that has reasonable PCIe hotplug support and won't panic at a device dropping off the bus, then you can just use a riser card that can control power provided over a PCIe slot.

Quarch makes power injection fixtures for basically all drive connectors, to be paired with their programmable power supply for power loss testing or voltage margin testing (quite important when M.2 drives pull 2.5+A over the 3.3V rail and still want <5% voltage drop).