diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
---|---|---|
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/flat_map.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 'library/core/tests/iter/adapters/flat_map.rs')
-rw-r--r-- | library/core/tests/iter/adapters/flat_map.rs | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/library/core/tests/iter/adapters/flat_map.rs b/library/core/tests/iter/adapters/flat_map.rs new file mode 100644 index 000000000..ee945e698 --- /dev/null +++ b/library/core/tests/iter/adapters/flat_map.rs @@ -0,0 +1,74 @@ +use core::iter::*; + +#[test] +fn test_iterator_flat_map() { + let xs = [0, 3, 6]; + let ys = [0, 1, 2, 3, 4, 5, 6, 7, 8]; + let it = xs.iter().flat_map(|&x| (x..).step_by(1).take(3)); + let mut i = 0; + for x in it { + assert_eq!(x, ys[i]); + i += 1; + } + assert_eq!(i, ys.len()); +} + +/// Tests `FlatMap::fold` with items already picked off the front and back, +/// to make sure all parts of the `FlatMap` are folded correctly. +#[test] +fn test_iterator_flat_map_fold() { + let xs = [0, 3, 6]; + let ys = [1, 2, 3, 4, 5, 6, 7]; + let mut it = xs.iter().flat_map(|&x| x..x + 3); + 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().flat_map(|&x| x..x + 3); + 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_flat_map_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).flat_map(mr).try_fold(7, f), (0..50).try_fold(7, f)); + assert_eq!((0..10).flat_map(mr).try_rfold(7, f), (0..50).try_rfold(7, f)); + let mut iter = (0..10).flat_map(mr); + 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).flat_map(|x| (4 * x)..(4 * x + 4)); + 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_double_ended_flat_map() { + let u = [0, 1]; + let v = [5, 6, 7, 8]; + let mut it = u.iter().flat_map(|x| &v[*x..v.len()]); + 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); +} |