Propagation delay is simple to implement:
Out <= '1' after 3ns;
I tried to add contamination delay as such:
Out <= '1' after 3ns; Out <= 'X' after 1ns;
Out would become undefined and then switch properly. However, in simulation I only observe the final assignment. [I'm using MultiSim to simulate, but this Quartus II link suggests it's normal to only observe the final assignment]
Is there a good way to simulate contamination delay?