What Australian cricket Test match did South Africa replace with a T20I in 2012?
Pakistani cricket team in South Africa in 2012–13:  South Africa announced their summer schedule of January–March in which they replaced their traditional Boxing Day Test with a T20I for the 2012–13 home season, during which they will host New Zealand and Pakistan. Boxing Day Test: The Boxing Day Test match is a cricket Test match held in Melbourne, Victoria, Australia involving the Australian cricket team and an opposing national team which is touring Australia during the southern summer.
Boxing Day Test