| use core::iter::*; |
| |
| #[test] |
| fn test_iterator_take_while() { |
| let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19]; |
| let ys = [0, 1, 2, 3, 5, 13]; |
| let it = xs.iter().take_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_take_while_folds() { |
| let f = &|acc, x| i32::checked_add(2 * acc, x); |
| assert_eq!((1..20).take_while(|&x| x != 10).try_fold(7, f), (1..10).try_fold(7, f)); |
| let mut iter = (1..20).take_while(|&x| x != 10); |
| assert_eq!(iter.try_fold(0, |x, y| Some(x + y)), Some((1..10).sum())); |
| assert_eq!(iter.next(), None, "flag should be set"); |
| let iter = (1..20).take_while(|&x| x != 10); |
| assert_eq!(iter.fold(0, |x, y| x + y), (1..10).sum()); |
| |
| let mut iter = (10..50).take_while(|&x| x != 40); |
| assert_eq!(iter.try_fold(0, i8::checked_add), None); |
| assert_eq!(iter.next(), Some(20)); |
| } |
