| use core::iter::*; |
| |
| #[test] |
| fn test_iterator_skip_while() { |
| let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19]; |
| let ys = [15, 16, 17, 19]; |
| let it = xs.iter().skip_while(|&x| *x < 15); |
| let mut i = 0; |
| for x in it { |
| assert_eq!(*x, ys[i]); |
| i += 1; |
| } |
| assert_eq!(i, ys.len()); |
| } |
| |
| #[test] |
| fn test_iterator_skip_while_fold() { |
| let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19]; |
| let ys = [15, 16, 17, 19]; |
| let it = xs.iter().skip_while(|&x| *x < 15); |
| let i = it.fold(0, |i, &x| { |
| assert_eq!(x, ys[i]); |
| i + 1 |
| }); |
| assert_eq!(i, ys.len()); |
| |
| let mut it = xs.iter().skip_while(|&x| *x < 15); |
| assert_eq!(it.next(), Some(&ys[0])); // process skips before folding |
| let i = it.fold(1, |i, &x| { |
| assert_eq!(x, ys[i]); |
| i + 1 |
| }); |
| assert_eq!(i, ys.len()); |
| } |
| |
| #[test] |
| fn test_skip_while_try_fold() { |
| let f = &|acc, x| i32::checked_add(2 * acc, x); |
| fn p(&x: &i32) -> bool { |
| (x % 10) <= 5 |
| } |
| assert_eq!((1..20).skip_while(p).try_fold(7, f), (6..20).try_fold(7, f)); |
| let mut iter = (1..20).skip_while(p); |
| assert_eq!(iter.nth(5), Some(11)); |
| assert_eq!(iter.try_fold(7, f), (12..20).try_fold(7, f)); |
| |
| let mut iter = (0..50).skip_while(|&x| (x % 20) < 15); |
| assert_eq!(iter.try_fold(0, i8::checked_add), None); |
| assert_eq!(iter.next(), Some(23)); |
| } |