The Helix Core C++ API has the ServerHelperApi [1] which can help create local servers on localhost. We can use it to create automated tests like that one created for GitAPI [2]

[1] https://www.perforce.com/manuals/p4api/Content/P4API/chapter.clientprogramming.serverhelperapi.html
[2] https://github.com/salesforce/p4-fusion/blob/master/tests/tests.git.h