anchor.diff:        directionSystem = null;
       });
       test("Testing main directions", () {
  -      testAddToMainDirection(directionSystem, Direction.MAIN_DIRECTIONS, 
  +      testAddToMainDirection(directionSystem, Direction.MAIN_DIRECTIONS,
             [{"x": 0,"y": -1}, {"x": 0,"y": 1},
              {"x": -1,"y": 0}, {"x": 1,"y": 0}], true);
       });
       test("Testing diagonal directions", () {
  -      testAddToMainDirection(directionSystem, Direction.DIAGONAL_DIRECTIONS, 
  +      testAddToMainDirection(directionSystem, Direction.DIAGONAL_DIRECTIONS,
             [{"x": -expectedDiagonalValue,"y": -expectedDiagonalValue},
              {"x": expectedDiagonalValue,"y": -expectedDiagonalValue},
              {"x": -expectedDiagonalValue,"y": expectedDiagonalValue},
  
positive.code:       directionSystem = null;
      });
      test("Testing diagonal directions", () {
        testSetMainDirection(directionSystem, Direction.MAIN_DIRECTIONS, 
            [{"x": 0,"y": -1}, {"x": 0,"y": 1},
             {"x": -1,"y": 0}, {"x": 1,"y": 0}]);
      });
      test("Testing diagonal directions", () {
        testSetMainDirection(directionSystem, Direction.DIAGONAL_DIRECTIONS, 
            [{"x": -expectedDiagonalValue,"y": -expectedDiagonalValue},
             {"x": expectedDiagonalValue,"y": -expectedDiagonalValue},
             {"x": -expectedDiagonalValue,"y": expectedDiagonalValue},
  
negative.code:     });
    });
  
    group("RotateDirections", () {
      DirectionSystem directionSystem;
      setUp(() {
        directionSystem = new DirectionSystem();
  