### Question:
HeuristicManhattan implements Heuristic { @Override public double getCost(int sx, int sy, int dx, int dy) { return minimumCost * (Math.abs(sx - (double) dx) + Math.abs(sy - (double) dy)); } HeuristicManhattan(int minimumCost); @Override double getCost(int sx, int sy, int dx, int dy);  }### Answer:
@Test void testHeuristic() { final Heuristic heuristic = new HeuristicManhattan(1); assertEquals(4.0, heuristic.getCost(1, 2, 3, 4)); }