Or better, integration test where multiple executables are involved, making regular in-process mocking unusable.

On Linux (well, glibc, not sure about other libc implementations) you can just set the `TZ` environment variable before running the app. I wonder if Windows has something similar.

Gimme gimme gimme? ;)

But not all, the author says: I get many email messages that say something like "I tried to extend the trial period of xyz software with RunAsDate and it didn't work". Running a software with different date/time can be used for many legitimate purposes and for these purposes RunAsDate was created. I have never said implicitly or explicitly that RunAsDate can be used for extending the trial period of a software. For some shareware programs, RunAsDate might really work, but many shareware creators are smart enough to detect that the date/time was modified and when they detect the time change, they end the trial period immediately. Please don't bother yourself to send me a question about extending the trial period of a software, because these kind of messages are simply deleted without answering.

Timed license or something? I’ve heard of SAS but have never used it. Any good?

If you don't need to worry about updates or litigation, just reverse engineer the date check and crack it.