[jakeinspace]

CI during the first phases of development in my experience is now often done with modern tooling (gitlab CI, Jenkins), compiling and running tests on a regular Linux x86 build server. Later phases switch over to some sort of emulated test harness, with interrupts coming from simulated flight hardware. Obviously the further along in the development process, the more expensive and slow it is to run tests. Maybe some software groups (SpaceX?) have a process that allows for tight test loops all the way to actual hardware in the loop tests.