tests/integration/grid_entity_e2e_test.py exercises the full
Grid + GridView + EntityBehavior stack over 100 turns with four
simultaneous entities on a 20x20 walled grid:
Player turn_order=0 manual placement, excluded from step()
Guard PATROL waypoints + target_label="player" + sight_radius=5
step() callback switches to SEEK on TARGET trigger
NPC NOISE8 random 8-directional wander
Trap SLEEP turns=10, DONE callback fires then reverts to IDLE
Player is placed near the (15,15) waypoint so the Guard both
patrols (visits >=1 waypoint) and engages SEEK once in sight.
Verifies trigger count, DONE step index, behavior_type reversion,
and no crashes / Python exceptions over the full 100-turn run.
Kanboard card 36.