Maighstir: "Virtual machines" is the only answer I can give you there. While Apple's license forbids running MacOS on non-Apple hardware, and MacOS has checks to make sure it is running on genuine Apple hardware, there are ways to get around or disable the check and you can always ignore the license.

You'll have to go look up articles, forum posts, and videos around the 'net for more information. "Hackintosh" is a search term that may help, though it most often refers to running on off-the-shelf PC hardware it may still be useful for virtualisation.