For the test, you can either add it tothis file or you can create another file in that directory.

Did you want to add a test or would you want to merge this as is?

I did try to add a test and found that the test passes either way, so maybe I should change the PR to just add the test instead of changing the code?

You mean, to make sure the test fails without the implementation of int extension?
If so, yes, you can push a test, remove the implementation to make sure the test fails and push back the implementation.