1. A method of testing a vehicle braking system, the method comprising: determining a nominal brake system parameter of the brake system during a braking operation; performing a first testing brake operation; determining a first brake system parameter based on the first testing brake operation; determining a tested brake system parameter based on the first brake system parameter; comparing the tested brake system parameter to the nominal brake system parameter; and setting a brake system compliance suspicion value of the vehicle braking system based on the comparison.