diff options
Diffstat (limited to 'library/core/tests/iter/adapters/enumerate.rs')
-rw-r--r-- | library/core/tests/iter/adapters/enumerate.rs | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/library/core/tests/iter/adapters/enumerate.rs b/library/core/tests/iter/adapters/enumerate.rs new file mode 100644 index 000000000..0e6033878 --- /dev/null +++ b/library/core/tests/iter/adapters/enumerate.rs @@ -0,0 +1,107 @@ +use core::iter::*; + +#[test] +fn test_iterator_enumerate() { + let xs = [0, 1, 2, 3, 4, 5]; + let it = xs.iter().enumerate(); + for (i, &x) in it { + assert_eq!(i, x); + } +} + +#[test] +fn test_iterator_enumerate_nth() { + let xs = [0, 1, 2, 3, 4, 5]; + for (i, &x) in xs.iter().enumerate() { + assert_eq!(i, x); + } + + let mut it = xs.iter().enumerate(); + while let Some((i, &x)) = it.nth(0) { + assert_eq!(i, x); + } + + let mut it = xs.iter().enumerate(); + while let Some((i, &x)) = it.nth(1) { + assert_eq!(i, x); + } + + let (i, &x) = xs.iter().enumerate().nth(3).unwrap(); + assert_eq!(i, x); + assert_eq!(i, 3); +} + +#[test] +fn test_iterator_enumerate_nth_back() { + let xs = [0, 1, 2, 3, 4, 5]; + let mut it = xs.iter().enumerate(); + while let Some((i, &x)) = it.nth_back(0) { + assert_eq!(i, x); + } + + let mut it = xs.iter().enumerate(); + while let Some((i, &x)) = it.nth_back(1) { + assert_eq!(i, x); + } + + let (i, &x) = xs.iter().enumerate().nth_back(3).unwrap(); + assert_eq!(i, x); + assert_eq!(i, 2); +} + +#[test] +fn test_iterator_enumerate_count() { + let xs = [0, 1, 2, 3, 4, 5]; + assert_eq!(xs.iter().enumerate().count(), 6); +} + +#[test] +fn test_iterator_enumerate_fold() { + let xs = [0, 1, 2, 3, 4, 5]; + let mut it = xs.iter().enumerate(); + // steal a couple to get an interesting offset + assert_eq!(it.next(), Some((0, &0))); + assert_eq!(it.next(), Some((1, &1))); + let i = it.fold(2, |i, (j, &x)| { + assert_eq!(i, j); + assert_eq!(x, xs[j]); + i + 1 + }); + assert_eq!(i, xs.len()); + + let mut it = xs.iter().enumerate(); + assert_eq!(it.next(), Some((0, &0))); + let i = it.rfold(xs.len() - 1, |i, (j, &x)| { + assert_eq!(i, j); + assert_eq!(x, xs[j]); + i - 1 + }); + assert_eq!(i, 0); +} + +#[test] +fn test_enumerate_try_folds() { + let f = &|acc, (i, x)| usize::checked_add(2 * acc, x / (i + 1) + i); + assert_eq!((9..18).enumerate().try_fold(7, f), (0..9).map(|i| (i, i + 9)).try_fold(7, f)); + assert_eq!((9..18).enumerate().try_rfold(7, f), (0..9).map(|i| (i, i + 9)).try_rfold(7, f)); + + let mut iter = (100..200).enumerate(); + let f = &|acc, (i, x)| u8::checked_add(acc, u8::checked_div(x, i as u8 + 1)?); + assert_eq!(iter.try_fold(0, f), None); + assert_eq!(iter.next(), Some((7, 107))); + assert_eq!(iter.try_rfold(0, f), None); + assert_eq!(iter.next_back(), Some((11, 111))); +} + +#[test] +fn test_double_ended_enumerate() { + let xs = [1, 2, 3, 4, 5, 6]; + let mut it = xs.iter().cloned().enumerate(); + assert_eq!(it.next(), Some((0, 1))); + assert_eq!(it.next(), Some((1, 2))); + assert_eq!(it.next_back(), Some((5, 6))); + assert_eq!(it.next_back(), Some((4, 5))); + assert_eq!(it.next_back(), Some((3, 4))); + assert_eq!(it.next_back(), Some((2, 3))); + assert_eq!(it.next(), None); +} |