Device which you can connect to a power supply i(e.g. PSU Powe Supply Unit in a computer) to test if it is working properly.
StarTech.com USB-C Power Tester, Digital Multimeter, Bi-Directional Voltage and Current Meter, Up to 240W PD EPR, Portable USB-C Cable and Port Power Meter Tester

StarTech.com USB-C Power Tester, Digital Multimeter, Bi-Directional Voltage and Current Meter, Up to 240W PD EPR, Portable USB-C Cable and Port Power Meter Tester

StarTech.com
£20.99
Plugable Technologies USB C Power Meter Tester for Monitoring USB-C Connections up to 240W - Digital Multimeter Tester for USB-C Cables, Laptops, Phones, Chargers - Driverless

Plugable Technologies USB C Power Meter Tester for Monitoring USB-C Connections up to 240W - Digital Multimeter Tester for USB-C Cables, Laptops, Phones, Chargers - Driverless

Plugable Technologies
£30.99
Plugable Technologies USB C Power Meter Tester for Monitoring USB-C Connections - Digital Multimeter for USB-C Cables, Laptops, Phones, Chargers - Driverless

Plugable Technologies USB C Power Meter Tester for Monitoring USB-C Connections - Digital Multimeter for USB-C Cables, Laptops, Phones, Chargers - Driverless

Plugable Technologies
£22.99