编写Junit程序访问私有属性

比如某一类中有如下私有属性

private Position position;

使用set方法修改了position

public void setPosition(Position position) {
		this.position = position;
		checkRep();
	}

如何在Junit程序中访问position，看其是否被修改？
代码如下：

Piece go = new Piece("fnd", 0, 1);
@Test
	public void setPositionTest() {
		Class<?> clazz = go.getClass();
		Field field;
		try {
			field = clazz.getDeclaredField("position");
			field.setAccessible(true);
			Position old;
			try {
				old = (Position)field.get(go); 
				assertEquals(new Position(0, 1),old);
				go.setPosition(new Position(2, 3));
				Position newPosition = (Position)field.get(go); 
				assertEquals(new Position(2, 3),newPosition);
			} catch (IllegalArgumentException | IllegalAccessException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}		
		} catch (NoSuchFieldException | SecurityException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}		
	}

如图所示，可以通过