It sounds like a useful test if you get a positive result for discrimination. If the test comes back negative, things are more complicated.

This isn't as simple as it seems because a supposed job requirement, while superficially neutral, may be unnecessary. For example, police departments used to have height requirements. But height requirements discriminate against women. Do you need to be tall to be a police officer? Maybe it's really about projecting authority? Okay, how do you measure that?

Making job requirements neutral is a rather fuzzy area. What is the job really about? Who decides?

Any variable that's not independent of gender can be used to (imperfectly) detect gender. It may not be easy to figure out if machine learning is using it for something real or just as a substitute gender-detector. Randomizing gender while leaving everything else the same isn't going to detect this.