That's why I asked which test.
There is no such test called A1.
A1 is just the current minimum level required.
There are actually quite a number of tests that can be taken.
Here's the latest UKBA approved listing for English tests
A pretty good starting point is to find a test centre close to where your wife is living.
Unless her English skills are pretty good already I suggest looking for a test that is actually evaluated at A1 level.
As I said before IELTS is evaluated at a higher level of B1 and obviously demands a better proficiency.
Hope that helps