java私有方法单元测试

使用junit5，类的代码为

package com.sysush.tool;
public class Tool1 {
    private void helloworld() {
        System.out.println("hello world");
    }
    private int add(Integer a, Integer b) {
        return a + b;
    }
}

测试代码为：

import org.junit.jupiter.api.Test;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class Tool1Test {
    private Tool1 tool = new Tool1();
    @Test
    public void noPara() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        Method privateMethod = tool.getClass().getDeclaredMethod("helloworld");
        privateMethod.setAccessible(true);
        privateMethod.invoke(tool);
    }
    @Test
    public void para() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        Method privateMethod = tool.getClass().getDeclaredMethod("add", Integer.class, Integer.class);
        privateMethod.setAccessible(true);
        Object a = privateMethod.invoke(tool, 1, 2);
        System.out.println(a);
    }
}