if your wife is under visit visa only she is not required to undergo medical test but if she is on family residence visa she will be required to undergo medical test in the country of point of origin. If she is here already you may apply for a family visa and this will require a medical test but for HIV and x-ray only. I am sharing only what i have underwent in the processing of my residence visa.

I came here on a visit visa only. When i arrived here my husband applied for my family residence visa when i am here already. medical test required for family visa is x-ray and HIV test only. I passed the medical test and now have the resident ID.

i hope this help. thanks