1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
|
//! Note
//! ----
//! You're probably viewing this file because you're adding a test (or you might
//! just be browsing, in that case, hey there!).
//!
//! If you've made a test that happens to use one of DoubleEnded's methods, but
//! it tests another adapter or trait, you should *add it to the adapter or
//! trait's test file*.
//!
//! Some examples would be `adapters::cloned::test_cloned_try_folds` or
//! `adapters::flat_map::test_double_ended_flat_map`, which use `try_fold` and
//! `next_back`, but test their own adapter.
#[test]
fn test_iterator_rev_nth_back() {
let v: &[_] = &[0, 1, 2, 3, 4];
for i in 0..v.len() {
assert_eq!(v.iter().rev().nth_back(i).unwrap(), &v[i]);
}
assert_eq!(v.iter().rev().nth_back(v.len()), None);
}
#[test]
fn test_iterator_rev_nth() {
let v: &[_] = &[0, 1, 2, 3, 4];
for i in 0..v.len() {
assert_eq!(v.iter().rev().nth(i).unwrap(), &v[v.len() - 1 - i]);
}
assert_eq!(v.iter().rev().nth(v.len()), None);
}
#[test]
fn test_rev() {
let xs = [2, 4, 6, 8, 10, 12, 14, 16];
let mut it = xs.iter();
it.next();
it.next();
assert!(it.rev().cloned().collect::<Vec<isize>>() == vec![16, 14, 12, 10, 8, 6]);
}
#[test]
fn test_rev_try_folds() {
let f = &|acc, x| i32::checked_add(2 * acc, x);
assert_eq!((1..10).rev().try_fold(7, f), (1..10).try_rfold(7, f));
assert_eq!((1..10).rev().try_rfold(7, f), (1..10).try_fold(7, f));
let a = [10, 20, 30, 40, 100, 60, 70, 80, 90];
let mut iter = a.iter().rev();
assert_eq!(iter.try_fold(0_i8, |acc, &x| acc.checked_add(x)), None);
assert_eq!(iter.next(), Some(&70));
let mut iter = a.iter().rev();
assert_eq!(iter.try_rfold(0_i8, |acc, &x| acc.checked_add(x)), None);
assert_eq!(iter.next_back(), Some(&60));
}
#[test]
fn test_rposition() {
fn f(xy: &(isize, char)) -> bool {
let (_x, y) = *xy;
y == 'b'
}
fn g(xy: &(isize, char)) -> bool {
let (_x, y) = *xy;
y == 'd'
}
let v = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')];
assert_eq!(v.iter().rposition(f), Some(3));
assert!(v.iter().rposition(g).is_none());
}
#[test]
fn test_rev_rposition() {
let v = [0, 0, 1, 1];
assert_eq!(v.iter().rev().rposition(|&x| x == 1), Some(1));
}
#[test]
#[should_panic]
fn test_rposition_panic() {
let u = (Box::new(0), Box::new(0));
let v: [(Box<_>, Box<_>); 4] = [u.clone(), u.clone(), u.clone(), u];
let mut i = 0;
v.iter().rposition(|_elt| {
if i == 2 {
panic!()
}
i += 1;
false
});
}
|
