The worst cost suggested by the heuristic

Property definitions

a_star $ PathContext :: worst_heuristic_cost
	# The worst cost suggested by the heuristic
	fun worst_heuristic_cost: Int is abstract
lib/a_star/a_star.nit:355,2--356,42

a_star $ ConstantPathContext :: worst_heuristic_cost
	redef fun worst_heuristic_cost do return 0
lib/a_star/a_star.nit:373,2--43

a_star $ WeightedPathContext :: worst_heuristic_cost
	redef fun worst_heuristic_cost do return 0
lib/a_star/a_star.nit:402,2--43

a_star $ PositionPathContext :: worst_heuristic_cost
	redef fun worst_heuristic_cost do return 100
lib/a_star/tests/test_a_star.nit:300,2--45