SolutionFactory { public static VehicleRoutingSolution emptySolution() { VehicleRoutingSolution solution = new VehicleRoutingSolution(); solution.setVisitList(new ArrayList<>()); solution.setDepotList(new ArrayList<>()); solution.setVehicleList(new ArrayList<>()); solution.setScore(HardSoftLongScore.ZERO); return solution; } private  SolutionFactory(); static VehicleRoutingSolution emptySolution(); static VehicleRoutingSolution solutionFromVisits(
            List<PlanningVehicle> vehicles,
            PlanningDepot depot,
            List<PlanningVisit> visits);  }
@Test void empty_solution_should_be_empty() { VehicleRoutingSolution solution = SolutionFactory.emptySolution(); assertThat(solution.getVisitList()).isEmpty(); assertThat(solution.getDepotList()).isEmpty(); assertThat(solution.getVehicleList()).isEmpty(); assertThat(solution.getScore()).isEqualTo(HardSoftLongScore.ZERO); }