SpaceX probably can't create a simulation in a few months to not need in-flight abort test because developing a simulation that NASA would consider "proof" probably takes years.
NASA has indicated today they are not going to rush commercial crew [1][3], to not press SpaceX and Boeing into go-fever which NASA has learned is very dangerous.
Because the timing of SpaceX DM-1 (uncrewed demo flight of crewed Dragon 2) depends on ISS visiting vehicle schedule, it might move to the left if visiting vehicle schedule gets reshuffled.
NASA has indicated in today's briefing that crew must be present on station to oversee commercial crew tests [2], so if ISS is de-crewed in December, SpaceX DM-1 can't go in January as scheduled.
3 - https://twitter.com/ChrisG_NSF/status/1050423979561824256
1 - https://twitter.com/ChrisG_NSF/status/1050423063655768065
2 - https://twitter.com/ChrisG_NSF/status/1050421610270752768