004 通过链表学Rust之测试

介绍

视频地址：https://www.bilibili.com/video/av78062009/
相关源码：https://github.com/anonymousGiga/Rust-link-list

详细内容

上一节我们已经完成了链表的基本功能。本节就对上一节的例子进行测试。
步骤如下：

cargo new mylist --lib

在mylist/src/lib.rs中写入如下代码：

use std::mem;

#[derive(Debug)]
pub struct List{
    head: Link,
}

#[derive(Debug)]
enum Link {
    Empty,
    More(Box<Node>),
}

#[derive(Debug)]
struct Node {
    elem: i32,
    next: Link,
}

impl List {
    pub fn new() -> Self {
        List { head: Link::Empty }
    }

    pub fn push(&mut self, elem: i32) {
        let node = Box::new(Node {
            elem: elem,
            next: mem::replace(&mut self.head, Link::Empty),
        });

        self.head = Link::More(node);
    }

    pub fn pop(&mut self) -> Option<i32> {
        match mem::replace(&mut self.head, Link::Empty) {
            Link::Empty => None,
            Link::More(node) => {
                self.head = node.next;
                Some(node.elem) 
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::List;

    #[test]
    fn basics() {
        let mut list = List::new();
        assert_eq!(list.pop(), None);

        list.push(1);
        list.push(2);
        list.push(3);

        assert_eq!(list.pop(), Some(3));
        assert_eq!(list.pop(), Some(2));

        list.push(4);
        list.push(5);

        assert_eq!(list.pop(), Some(5));
        assert_eq!(list.pop(), Some(4));

        assert_eq!(list.pop(), Some(1));
        assert_eq!(list.pop(), None);
    }

}

运行测试如下：

cargo test