When unit testing without a host application, where do I put files?

When running a unit test without a host application, my code for creating a file is returning something in the CoreSimulator. However that location doesn't necessarily exist.

This is my code:

let searchPaths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)

let documentFolderPath = searchPaths[0]

let dbFilePath = documentFolderPath + "/test.db"

dbFilePath created:

/Users/aaronbratcher/Library/Developer/CoreSimulator/Devices/3E6F7BD3-482B-4A90-B3C7-C0CC8412A5AC/data/Documents/test.db

How can I get a path outside of CoreSimulator when running unit tests without a host app?