The Fear rating of a character can change during combat with the right combination of armour histories and attack patterns. So do characters force a fear test only when they are first seen, only when they engage in combat with a higher fear rating, or both?
Brother Dante of the Blood Angels walks out of a bunker to spy a horde of traitor guardsmen 15m away from him. His armour has both the "Blood of the Enemy" and "Terror Be Thy Friend" armour histories, giving him Fear (1) and +1 Fear in melee respectively. He is not in melee currently, so he counts as Fear (1).
On his next turn, Brother Dante uses the Crimson Tide attack pattern to charge the horde. He is now in melee so "Terror Be Thy Friend" comes into play, raising Fear to (2). But Crimson Tide adds to Fear too, so Brother Dante now has Fear (3) as he strikes the horde.
At what point(s) would Brother Dante force Fear tests on the horde and at what Fear rating?
to answer your question, each time a new condition which causes Fear is brought up in an encounter, the target must make a new test at the new value. Thus, in your example, the horde of traitor guardsmen would have to take a Willpower Test against Fear (1) when they first see Brother Dante. Then, when the horde gets into melee with Brother Dante, they must take another Willpower Test against Fear (2). At last, when Crimson Tide comes into effect, the traitor guardsmen must take a third Willpower Test against Fear (3).
Thank you for your question,