An email alert from DVSA details the procedure for the actual driving test. You can read the full communication by clicking the link, but the important part is as follows:
Wearing glasses with face coverings on test
Your pupil must wear a face covering when they come for their driving test, unless they have a good reason not to. This includes if:
- they have a physical or mental illness or impairment, or a disability that means they cannot put on, wear or remove a face covering
- putting on, wearing or removing a face covering would cause them severe distress
- they need to remove it during their test to avoid harm or injury or the risk of harm or injury to others
If your pupils wear glasses
Wearing glasses does not count as a good reason not to wear a face covering.
So, anyone going out on test must wear a face mask unless they have one of the excuses outlined, and wearing glasses is not an excuse not to.