Integer overflow errors were fixed in 4 error handlers: surrogatepass, backslashreplace, namereplace, and xmlcharrefreplace. Is is hard to write general robust tests. In worst cases they requires more than sys.maxsize or even sys.maxsize*2 memory and for sure fail with MemoryError. It is possible to write a test for xmlcharrefreplace, but it will not robust, after changes of implementation details it could raise MemoryError instead of OverflowError after consuming all address space.

So I suggest close this issue without tests. Such tests are useless.