6.7 测试

3 分钟阅读

原文链接: https://rust-unofficial.github.io/too-many-lists/sixth-testing.html

好吧，我拖了一阵子才写测试，因为嘛，我们都知道自己现在已经是 Rust 大师、不会再犯错了！而且这只是重写一个旧 crate，测试本来就有。测试嘛，你已经看过很多了。给：

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

    fn generate_test() -> LinkedList<i32> {
        list_from(&[0, 1, 2, 3, 4, 5, 6])
    }

    fn list_from<T: Clone>(v: &[T]) -> LinkedList<T> {
        v.iter().map(|x| (*x).clone()).collect()
    }

    #[test]
    fn test_basic_front() {
        let mut list = LinkedList::new();

        // 试着搞坏空链表
        assert_eq!(list.len(), 0);
        assert_eq!(list.pop_front(), None);
        assert_eq!(list.len(), 0);

        // 试着搞坏只有一个元素的链表
        list.push_front(10);
        assert_eq!(list.len(), 1);
        assert_eq!(list.pop_front(), Some(10));
        assert_eq!(list.len(), 0);
        assert_eq!(list.pop_front(), None);
        assert_eq!(list.len(), 0);

        // 随便折腾
        list.push_front(10);
        assert_eq!(list.len(), 1);
        list.push_front(20);
        assert_eq!(list.len(), 2);
        list.push_front(30);
        assert_eq!(list.len(), 3);
        assert_eq!(list.pop_front(), Some(30));
        assert_eq!(list.len(), 2);
        list.push_front(40);
        assert_eq!(list.len(), 3);
        assert_eq!(list.pop_front(), Some(40));
        assert_eq!(list.len(), 2);
        assert_eq!(list.pop_front(), Some(20));
        assert_eq!(list.len(), 1);
        assert_eq!(list.pop_front(), Some(10));
        assert_eq!(list.len(), 0);
        assert_eq!(list.pop_front(), None);
        assert_eq!(list.len(), 0);
        assert_eq!(list.pop_front(), None);
        assert_eq!(list.len(), 0);
    }

    #[test]
    fn test_basic() {
        let mut m = LinkedList::new();
        assert_eq!(m.pop_front(), None);
        assert_eq!(m.pop_back(), None);
        assert_eq!(m.pop_front(), None);
        m.push_front(1);
        assert_eq!(m.pop_front(), Some(1));
        m.push_back(2);
        m.push_back(3);
        assert_eq!(m.len(), 2);
        assert_eq!(m.pop_front(), Some(2));
        assert_eq!(m.pop_front(), Some(3));
        assert_eq!(m.len(), 0);
        assert_eq!(m.pop_front(), None);
        m.push_back(1);
        m.push_back(3);
        m.push_back(5);
        m.push_back(7);
        assert_eq!(m.pop_front(), Some(1));

        let mut n = LinkedList::new();
        n.push_front(2);
        n.push_front(3);
        {
            assert_eq!(n.front().unwrap(), &3);
            let x = n.front_mut().unwrap();
            assert_eq!(*x, 3);
            *x = 0;
        }
        {
            assert_eq!(n.back().unwrap(), &2);
            let y = n.back_mut().unwrap();
            assert_eq!(*y, 2);
            *y = 1;
        }
        assert_eq!(n.pop_front(), Some(0));
        assert_eq!(n.pop_front(), Some(1));
    }

    #[test]
    fn test_iterator() {
        let m = generate_test();
        for (i, elt) in m.iter().enumerate() {
            assert_eq!(i as i32, *elt);
        }
        let mut n = LinkedList::new();
        assert_eq!(n.iter().next(), None);
        n.push_front(4);
        let mut it = n.iter();
        assert_eq!(it.size_hint(), (1, Some(1)));
        assert_eq!(it.next().unwrap(), &4);
        assert_eq!(it.size_hint(), (0, Some(0)));
        assert_eq!(it.next(), None);
    }

    #[test]
    fn test_iterator_double_end() {
        let mut n = LinkedList::new();
        assert_eq!(n.iter().next(), None);
        n.push_front(4);
        n.push_front(5);
        n.push_front(6);
        let mut it = n.iter();
        assert_eq!(it.size_hint(), (3, Some(3)));
        assert_eq!(it.next().unwrap(), &6);
        assert_eq!(it.size_hint(), (2, Some(2)));
        assert_eq!(it.next_back().unwrap(), &4);
        assert_eq!(it.size_hint(), (1, Some(1)));
        assert_eq!(it.next_back().unwrap(), &5);
        assert_eq!(it.next_back(), None);
        assert_eq!(it.next(), None);
    }

    #[test]
    fn test_rev_iter() {
        let m = generate_test();
        for (i, elt) in m.iter().rev().enumerate() {
            assert_eq!(6 - i as i32, *elt);
        }
        let mut n = LinkedList::new();
        assert_eq!(n.iter().rev().next(), None);
        n.push_front(4);
        let mut it = n.iter().rev();
        assert_eq!(it.size_hint(), (1, Some(1)));
        assert_eq!(it.next().unwrap(), &4);
        assert_eq!(it.size_hint(), (0, Some(0)));
        assert_eq!(it.next(), None);
    }

    #[test]
    fn test_mut_iter() {
        let mut m = generate_test();
        let mut len = m.len();
        for (i, elt) in m.iter_mut().enumerate() {
            assert_eq!(i as i32, *elt);
            len -= 1;
        }
        assert_eq!(len, 0);
        let mut n = LinkedList::new();
        assert!(n.iter_mut().next().is_none());
        n.push_front(4);
        n.push_back(5);
        let mut it = n.iter_mut();
        assert_eq!(it.size_hint(), (2, Some(2)));
        assert!(it.next().is_some());
        assert!(it.next().is_some());
        assert_eq!(it.size_hint(), (0, Some(0)));
        assert!(it.next().is_none());
    }

    #[test]
    fn test_iterator_mut_double_end() {
        let mut n = LinkedList::new();
        assert!(n.iter_mut().next_back().is_none());
        n.push_front(4);
        n.push_front(5);
        n.push_front(6);
        let mut it = n.iter_mut();
        assert_eq!(it.size_hint(), (3, Some(3)));
        assert_eq!(*it.next().unwrap(), 6);
        assert_eq!(it.size_hint(), (2, Some(2)));
        assert_eq!(*it.next_back().unwrap(), 4);
        assert_eq!(it.size_hint(), (1, Some(1)));
        assert_eq!(*it.next_back().unwrap(), 5);
        assert!(it.next_back().is_none());
        assert!(it.next().is_none());
    }

    #[test]
    fn test_eq() {
        let mut n: LinkedList<u8> = list_from(&[]);
        let mut m = list_from(&[]);
        assert!(n == m);
        n.push_front(1);
        assert!(n != m);
        m.push_back(1);
        assert!(n == m);

        let n = list_from(&[2, 3, 4]);
        let m = list_from(&[1, 2, 3]);
        assert!(n != m);
    }

    #[test]
    fn test_ord() {
        let n = list_from(&[]);
        let m = list_from(&[1, 2, 3]);
        assert!(n < m);
        assert!(m > n);
        assert!(n <= n);
        assert!(n >= n);
    }

    #[test]
    fn test_ord_nan() {
        let nan = 0.0f64 / 0.0;
        let n = list_from(&[nan]);
        let m = list_from(&[nan]);
        assert!(!(n < m));
        assert!(!(n > m));
        assert!(!(n <= m));
        assert!(!(n >= m));

        let n = list_from(&[nan]);
        let one = list_from(&[1.0f64]);
        assert!(!(n < one));
        assert!(!(n > one));
        assert!(!(n <= one));
        assert!(!(n >= one));

        let u = list_from(&[1.0f64, 2.0, nan]);
        let v = list_from(&[1.0f64, 2.0, 3.0]);
        assert!(!(u < v));
        assert!(!(u > v));
        assert!(!(u <= v));
        assert!(!(u >= v));

        let s = list_from(&[1.0f64, 2.0, 4.0, 2.0]);
        let t = list_from(&[1.0f64, 2.0, 3.0, 2.0]);
        assert!(!(s < t));
        assert!(s > one);
        assert!(!(s <= one));
        assert!(s >= one);
    }

    #[test]
    fn test_debug() {
        let list: LinkedList<i32> = (0..10).collect();
        assert_eq!(format!("{:?}", list), "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]");

        let list: LinkedList<&str> = vec!["just", "one", "test", "more"]
            .iter().copied()
            .collect();
        assert_eq!(format!("{:?}", list), r#"["just", "one", "test", "more"]"#);
    }

    #[test]
    fn test_hashmap() {
        // 检查 HashMap 能否把它当作 key 用

        let list1: LinkedList<i32> = (0..10).collect();
        let list2: LinkedList<i32> = (1..11).collect();
        let mut map = std::collections::HashMap::new();

        assert_eq!(map.insert(list1.clone(), "list1"), None);
        assert_eq!(map.insert(list2.clone(), "list2"), None);

        assert_eq!(map.len(), 2);

        assert_eq!(map.get(&list1), Some(&"list1"));
        assert_eq!(map.get(&list2), Some(&"list2"));

        assert_eq!(map.remove(&list1), Some("list1"));
        assert_eq!(map.remove(&list2), Some("list2"));

        assert!(map.is_empty());
    }
}

关键时刻到了：

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cargo test
    Finished test [unoptimized + debuginfo] target(s) in 0.00s
     Running unittests src\lib.rs

running 12 tests
test test::test_basic ... ok
test test::test_basic_front ... ok
test test::test_eq ... ok
test test::test_iterator ... ok
test test::test_iterator_mut_double_end ... ok
test test::test_ord_nan ... ok
test test::test_iterator_double_end ... ok
test test::test_mut_iter ... ok
test test::test_rev_iter ... ok
test test::test_hashmap ... ok
test test::test_ord ... ok
test test::test_debug ... ok

test result: ok. 12 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

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$env:MIRIFLAGS="-Zmiri-tag-raw-pointers"
cargo miri test
   Compiling linked-list v0.0.3
    Finished test [unoptimized + debuginfo] target(s) in 0.35s
     Running unittests src\lib.rs

running 12 tests
test test::test_basic ... ok
test test::test_basic_front ... ok
test test::test_debug ... ok
test test::test_eq ... ok
test test::test_hashmap ... ok
test test::test_iterator ... ok
test test::test_iterator_double_end ... ok
test test::test_iterator_mut_double_end ... ok
test test::test_mut_iter ... ok
test test::test_ord ... ok
test test::test_ord_nan ... ok
test test::test_rev_iter ... ok

test result: ok. 12 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

😭

我们做到了，居然真的没搞砸。这不是套路！所有练习和训练终于值了，我们终于写出了好代码！！！

现在这些杂活都清掉了，可以回到有趣的东西了！

最后修改 August 23, 2026: 更新 (499855b16)