diff options
Diffstat (limited to 'library/core/tests/iter/adapters/take_while.rs')
-rw-r--r-- | library/core/tests/iter/adapters/take_while.rs | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/library/core/tests/iter/adapters/take_while.rs b/library/core/tests/iter/adapters/take_while.rs new file mode 100644 index 000000000..6f1ebab29 --- /dev/null +++ b/library/core/tests/iter/adapters/take_while.rs @@ -0,0 +1,29 @@ +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)); +} |