| use core::iter::*; |
| |
| #[test] |
| fn test_map_try_folds() { |
| let f = &|acc, x| i32::checked_add(2 * acc, x); |
| assert_eq!((0..10).map(|x| x + 3).try_fold(7, f), (3..13).try_fold(7, f)); |
| assert_eq!((0..10).map(|x| x + 3).try_rfold(7, f), (3..13).try_rfold(7, f)); |
| |
| let mut iter = (0..40).map(|x| x + 10); |
| assert_eq!(iter.try_fold(0, i8::checked_add), None); |
| assert_eq!(iter.next(), Some(20)); |
| assert_eq!(iter.try_rfold(0, i8::checked_add), None); |
| assert_eq!(iter.next_back(), Some(46)); |
| } |
| |
| #[test] |
| fn test_double_ended_map() { |
| let xs = [1, 2, 3, 4, 5, 6]; |
| let mut it = xs.iter().map(|&x| x * -1); |
| assert_eq!(it.next(), Some(-1)); |
| assert_eq!(it.next(), Some(-2)); |
| assert_eq!(it.next_back(), Some(-6)); |
| assert_eq!(it.next_back(), Some(-5)); |
| assert_eq!(it.next(), Some(-3)); |
| assert_eq!(it.next_back(), Some(-4)); |
| assert_eq!(it.next(), None); |
| } |
