Transport Canada has said they are going to be much more involved;
https://www.cbc.ca/news/politics/boe...ests-1.5476130
Though national authorities generally credit each other's certification work in large part, Transport Canada is exercising the right to increase their involvement in this case. When Transport Canada involves itself in its own delegate's work, it's referred to as surveillance, which is part of the TC mandate for their service to the public. When they involve themselves in another authority's certification program, it's not surveillance, is an indication in a gap in confidence in that authority's certification process.
During this testing, the FAA and Boeing will know to present their very best certification process - which we would hope that the FAA and Boeing are doing all the time!
It would be interesting in this context to hear how EASA will involve itself in return to service certification testing.....