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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /library/core/tests/iter/adapters/flatten.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | library/core/tests/iter/adapters/flatten.rs | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/library/core/tests/iter/adapters/flatten.rs b/library/core/tests/iter/adapters/flatten.rs new file mode 100644 index 000000000..f8ab8c9d4 --- /dev/null +++ b/library/core/tests/iter/adapters/flatten.rs @@ -0,0 +1,170 @@ +use super::*; +use core::iter::*; + +#[test] +fn test_iterator_flatten() { + let xs = [0, 3, 6]; + let ys = [0, 1, 2, 3, 4, 5, 6, 7, 8]; + let it = xs.iter().map(|&x| (x..).step_by(1).take(3)).flatten(); + let mut i = 0; + for x in it { + assert_eq!(x, ys[i]); + i += 1; + } + assert_eq!(i, ys.len()); +} + +/// Tests `Flatten::fold` with items already picked off the front and back, +/// to make sure all parts of the `Flatten` are folded correctly. +#[test] +fn test_iterator_flatten_fold() { + let xs = [0, 3, 6]; + let ys = [1, 2, 3, 4, 5, 6, 7]; + let mut it = xs.iter().map(|&x| x..x + 3).flatten(); + assert_eq!(it.next(), Some(0)); + assert_eq!(it.next_back(), Some(8)); + let i = it.fold(0, |i, x| { + assert_eq!(x, ys[i]); + i + 1 + }); + assert_eq!(i, ys.len()); + + let mut it = xs.iter().map(|&x| x..x + 3).flatten(); + assert_eq!(it.next(), Some(0)); + assert_eq!(it.next_back(), Some(8)); + let i = it.rfold(ys.len(), |i, x| { + assert_eq!(x, ys[i - 1]); + i - 1 + }); + assert_eq!(i, 0); +} + +#[test] +fn test_flatten_try_folds() { + let f = &|acc, x| i32::checked_add(acc * 2 / 3, x); + let mr = &|x| (5 * x)..(5 * x + 5); + assert_eq!((0..10).map(mr).flatten().try_fold(7, f), (0..50).try_fold(7, f)); + assert_eq!((0..10).map(mr).flatten().try_rfold(7, f), (0..50).try_rfold(7, f)); + let mut iter = (0..10).map(mr).flatten(); + iter.next(); + iter.next_back(); // have front and back iters in progress + assert_eq!(iter.try_rfold(7, f), (1..49).try_rfold(7, f)); + + let mut iter = (0..10).map(|x| (4 * x)..(4 * x + 4)).flatten(); + assert_eq!(iter.try_fold(0, i8::checked_add), None); + assert_eq!(iter.next(), Some(17)); + assert_eq!(iter.try_rfold(0, i8::checked_add), None); + assert_eq!(iter.next_back(), Some(35)); +} + +#[test] +fn test_flatten_advance_by() { + let mut it = once(0..10).chain(once(10..30)).chain(once(30..40)).flatten(); + + it.advance_by(5).unwrap(); + assert_eq!(it.next(), Some(5)); + it.advance_by(9).unwrap(); + assert_eq!(it.next(), Some(15)); + it.advance_back_by(4).unwrap(); + assert_eq!(it.next_back(), Some(35)); + it.advance_back_by(9).unwrap(); + assert_eq!(it.next_back(), Some(25)); + + assert_eq!(it.advance_by(usize::MAX), Err(9)); + assert_eq!(it.advance_back_by(usize::MAX), Err(0)); + it.advance_by(0).unwrap(); + it.advance_back_by(0).unwrap(); + assert_eq!(it.size_hint(), (0, Some(0))); +} + +#[test] +fn test_flatten_non_fused_outer() { + let mut iter = NonFused::new(once(0..2)).flatten(); + + assert_eq!(iter.next_back(), Some(1)); + assert_eq!(iter.next(), Some(0)); + assert_eq!(iter.next(), None); + assert_eq!(iter.next(), None); + + let mut iter = NonFused::new(once(0..2)).flatten(); + + assert_eq!(iter.next(), Some(0)); + assert_eq!(iter.next_back(), Some(1)); + assert_eq!(iter.next_back(), None); + assert_eq!(iter.next_back(), None); +} + +#[test] +fn test_flatten_non_fused_inner() { + let mut iter = once(0..1).chain(once(1..3)).flat_map(NonFused::new); + + assert_eq!(iter.next_back(), Some(2)); + assert_eq!(iter.next(), Some(0)); + assert_eq!(iter.next(), Some(1)); + assert_eq!(iter.next(), None); + assert_eq!(iter.next(), None); + + let mut iter = once(0..1).chain(once(1..3)).flat_map(NonFused::new); + + assert_eq!(iter.next(), Some(0)); + assert_eq!(iter.next_back(), Some(2)); + assert_eq!(iter.next_back(), Some(1)); + assert_eq!(iter.next_back(), None); + assert_eq!(iter.next_back(), None); +} + +#[test] +fn test_double_ended_flatten() { + let u = [0, 1]; + let v = [5, 6, 7, 8]; + let mut it = u.iter().map(|x| &v[*x..v.len()]).flatten(); + assert_eq!(it.next_back().unwrap(), &8); + assert_eq!(it.next().unwrap(), &5); + assert_eq!(it.next_back().unwrap(), &7); + assert_eq!(it.next_back().unwrap(), &6); + assert_eq!(it.next_back().unwrap(), &8); + assert_eq!(it.next().unwrap(), &6); + assert_eq!(it.next_back().unwrap(), &7); + assert_eq!(it.next_back(), None); + assert_eq!(it.next(), None); + assert_eq!(it.next_back(), None); +} + +#[test] +fn test_trusted_len_flatten() { + fn assert_trusted_len<T: TrustedLen>(_: &T) {} + let mut iter = IntoIterator::into_iter([[0; 3]; 4]).flatten(); + assert_trusted_len(&iter); + + assert_eq!(iter.size_hint(), (12, Some(12))); + iter.next(); + assert_eq!(iter.size_hint(), (11, Some(11))); + iter.next_back(); + assert_eq!(iter.size_hint(), (10, Some(10))); + + let iter = IntoIterator::into_iter([[(); usize::MAX]; 1]).flatten(); + assert_eq!(iter.size_hint(), (usize::MAX, Some(usize::MAX))); + + let iter = IntoIterator::into_iter([[(); usize::MAX]; 2]).flatten(); + assert_eq!(iter.size_hint(), (usize::MAX, None)); + + let mut a = [(); 10]; + let mut b = [(); 10]; + + let iter = IntoIterator::into_iter([&mut a, &mut b]).flatten(); + assert_trusted_len(&iter); + assert_eq!(iter.size_hint(), (20, Some(20))); + core::mem::drop(iter); + + let iter = IntoIterator::into_iter([&a, &b]).flatten(); + assert_trusted_len(&iter); + assert_eq!(iter.size_hint(), (20, Some(20))); + + let iter = [(), (), ()].iter().flat_map(|_| [(); 1000]); + assert_trusted_len(&iter); + assert_eq!(iter.size_hint(), (3000, Some(3000))); + + let iter = [(), ()].iter().flat_map(|_| &a); + assert_trusted_len(&iter); + assert_eq!(iter.size_hint(), (20, Some(20))); +} |