Question about Covid test requirements on Alaska Air for US flights into Canada:

Can anyone confirm they were not required to prove a negative test result to the airline on the US to US portion of a connecting flight from the US to Canada?

Because of the timing of my flight, time zones, long connection time of 6 hours, and testing times at Walgreens (10am-4:45pm), my testing window will be tight ... about 40 hours from testing time to flight checkin, and 52 hours from CAD flight departure.

If my test results aren't back by the time I check in for my flights, will the Alaska Airlines still allow me to board the US-bound portion of my flight?