Testing a Custom Driver without being Wired

[AlessandroLodi]

Following an email exchange, I am posting here the back-and-forth I had with @jenshnielsen. I thank him for both enforcing the correct contribution behavior (writing here instead of personal communications) and for the answer he provided.

Question

I'm currently working on developing a custom driver for a Keithley 6517A electrometer using QCoDeS. As the instrument is not always physically available for testing, I'm looking for a way to test my driver implementation without connecting to the actual hardware.

I've been trying to use the DummyInstrument class for this purpose but without success. I'm therefore wondering if there's a recommended way to pass a custom-made driver written with QCoDeS to a DummyInstrument (or another class) for testing purposes.

My current approach involves something like this:

from qcodes.instrument_drivers.mock_instruments import DummyInstrument
from my_custom_driver import Keithley_6517A

mock_instrument = DummyInstrument(name="mock_keithley")
keithley_instance = Keithley_6517A(name="keithley", address="GPIB::15::INSTR", visa_handle=mock_instrument)

Answer

There are no great solutions but for simple tests you may want to consider pyvisa-sim.
This enables you to write a yaml file that defines simple request response patterns. We have a bunch of drivers in qcodes that have tests written that way that you may want to consult.