Ah, sorry, that’s a good question.

The good news is that FDB has a fairly opaque platform abstraction, and deterministic simulation tests for everything above it, so the vast majority of continuous testing in terms of CPU cycles can be run on Linux.

The only thing that really needs to run on a Mac are tests for changes to the build or packaging system, or to the MacOS implementation of the platform layer. My sense is those changes are pretty rare.

I don’t know whether the FDB team has an official recommendation for MacOS CI. I’d recommend posting a question on the forums: http://forums.foundationdb.org