anchor.diff:    for (int i = 0; i < directions.length; i++) {
       testDirection(directionSystem.getDirection(directions[i]), expectedDirections[i]["x"], expectedDirections[i]["y"]);
     }
  -}
  -
  -num _makeRadians(num angles) => angles * (PI / 180);
  +}
positive.code: }
  
  void testDirectionRange(direction, startX, endX, startY, endY) {
    expect(direction.x, inExclusiveRange(startX, endX));
    expect(direction.y, inExclusiveRange(startY, endY));
  }
  
  void testAddToMainDirection(DirectionSystem directionSystem, List directions, List<Map> expectedDirections, bool doNullMainDirection) {
  
negative.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},
             {"x": expectedDiagonalValue,"y": expectedDiagonalValue}]);
      });
    });
  
  