1 // run-pass
2
3 use std::fmt::Debug;
4 use std::cmp::{self, PartialOrd, Ordering};
5
6 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
7 struct Foo {
8 n: u8,
9 name: &'static str
10 }
11
12 impl PartialOrd for Foo {
partial_cmp(&self, other: &Foo) -> Option<Ordering>13 fn partial_cmp(&self, other: &Foo) -> Option<Ordering> {
14 Some(self.cmp(other))
15 }
16 }
17
18 impl Ord for Foo {
cmp(&self, other: &Foo) -> Ordering19 fn cmp(&self, other: &Foo) -> Ordering {
20 self.n.cmp(&other.n)
21 }
22 }
23
main()24 fn main() {
25 let a = Foo { n: 4, name: "a" };
26 let b = Foo { n: 4, name: "b" };
27 let c = Foo { n: 8, name: "c" };
28 let d = Foo { n: 8, name: "d" };
29 let e = Foo { n: 22, name: "e" };
30 let f = Foo { n: 22, name: "f" };
31
32 let data = [a, b, c, d, e, f];
33
34 // `min` should return the left when the values are equal
35 assert_eq!(data.iter().min(), Some(&a));
36 assert_eq!(data.iter().min_by_key(|a| a.n), Some(&a));
37 assert_eq!(cmp::min(a, b), a);
38 assert_eq!(cmp::min(b, a), b);
39
40 // `max` should return the right when the values are equal
41 assert_eq!(data.iter().max(), Some(&f));
42 assert_eq!(data.iter().max_by_key(|a| a.n), Some(&f));
43 assert_eq!(cmp::max(e, f), f);
44 assert_eq!(cmp::max(f, e), e);
45
46 let mut presorted = data.to_vec();
47 presorted.sort();
48 assert_stable(&presorted);
49
50 let mut presorted = data.to_vec();
51 presorted.sort_by(|a, b| a.cmp(b));
52 assert_stable(&presorted);
53
54 // Assert that sorted and min/max are the same
55 fn assert_stable<T: Ord + Debug>(presorted: &[T]) {
56 for slice in presorted.windows(2) {
57 let a = &slice[0];
58 let b = &slice[1];
59
60 assert_eq!(a, cmp::min(a, b));
61 assert_eq!(b, cmp::max(a, b));
62 }
63 }
64 }
65