The European Institute for Computer Antivirus Research (EICAR) has a file that can be used to test the capabilities/effectiveness of most Anti-Virus software, including Xprotect. The link below has some scary text but I had no trouble with Sophos Home Edition trapping and deleting the four versions of the file. I have not disabled the Sophos app to see how well Xprotect does. I will leave that as an exercise for the reader.
