Open the trunk and LOOK ??
You could carry a "donut" spare in any of them, although you might not like the loss of space in the trunk or hatch of some models.
If this is REALLY that important to you, have the agency OWNER sign a statement that says any car you are interested in HAS or can have a spare tire installed....and that any subsequent deal will be VOID if it is not present. Do this BEFORE you sign anything else.