test voltage, current, and resistance in one device.

I don't quite grasp it, but presumably some of you will. Either way, it's interesting:

Scientists Are About to Change the Way We Measure Electricity Forever
The National Institute of Standards and Technology (NIST) says it can now test voltage, current, and resistance in one device.

... Everything from high-flying planes to the smallest of microchips is reliant on accurate electrical standards, measurements based on the fundamental constants of nature that can help calibrate equipment used to power the foundation of our modern world. ...

.. In a new paper published in the journal Nature Electronics, scientists at NIST successfully developed an all-in-one, four-square-meter device that can calibrate ohms, amperes, and volts at the same time.

Oh! Forgot to add link! https://www.popularmechanics.com/science/a65823105/electrical-standards/