diff options
Diffstat (limited to 'library/core/tests/iter/adapters/map_windows.rs')
-rw-r--r-- | library/core/tests/iter/adapters/map_windows.rs | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/library/core/tests/iter/adapters/map_windows.rs b/library/core/tests/iter/adapters/map_windows.rs new file mode 100644 index 000000000..7fb2408f8 --- /dev/null +++ b/library/core/tests/iter/adapters/map_windows.rs @@ -0,0 +1,283 @@ +use std::sync::atomic::{AtomicUsize, Ordering::SeqCst}; + +#[cfg(not(panic = "abort"))] +mod drop_checks { + //! These tests mainly make sure the elements are correctly dropped. + use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering::SeqCst}; + + #[derive(Debug)] + struct DropInfo { + dropped_twice: AtomicBool, + alive_count: AtomicUsize, + } + + impl DropInfo { + const fn new() -> Self { + Self { dropped_twice: AtomicBool::new(false), alive_count: AtomicUsize::new(0) } + } + + #[track_caller] + fn check(&self) { + assert!(!self.dropped_twice.load(SeqCst), "a value was dropped twice"); + assert_eq!(self.alive_count.load(SeqCst), 0); + } + } + + #[derive(Debug)] + struct DropCheck<'a> { + info: &'a DropInfo, + was_dropped: bool, + } + + impl<'a> DropCheck<'a> { + fn new(info: &'a DropInfo) -> Self { + info.alive_count.fetch_add(1, SeqCst); + + Self { info, was_dropped: false } + } + } + + impl Drop for DropCheck<'_> { + fn drop(&mut self) { + if self.was_dropped { + self.info.dropped_twice.store(true, SeqCst); + } + self.was_dropped = true; + + self.info.alive_count.fetch_sub(1, SeqCst); + } + } + + fn iter(info: &DropInfo, len: usize, panic_at: usize) -> impl Iterator<Item = DropCheck<'_>> { + (0..len).map(move |i| { + if i == panic_at { + panic!("intended panic"); + } + DropCheck::new(info) + }) + } + + #[track_caller] + fn check<const N: usize>(len: usize, panic_at: usize) { + check_drops(|info| { + iter(info, len, panic_at).map_windows(|_: &[_; N]| {}).last(); + }); + } + + #[track_caller] + fn check_drops(f: impl FnOnce(&DropInfo)) { + let info = DropInfo::new(); + let _ = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| { + f(&info); + })); + info.check(); + } + + #[test] + fn no_iter_panic_n1() { + check::<1>(0, 100); + check::<1>(1, 100); + check::<1>(2, 100); + check::<1>(13, 100); + } + + #[test] + fn no_iter_panic_n2() { + check::<2>(0, 100); + check::<2>(1, 100); + check::<2>(2, 100); + check::<2>(3, 100); + check::<2>(13, 100); + } + + #[test] + fn no_iter_panic_n5() { + check::<5>(0, 100); + check::<5>(1, 100); + check::<5>(2, 100); + check::<5>(13, 100); + check::<5>(30, 100); + } + + #[test] + fn panic_in_first_batch() { + check::<1>(7, 0); + + check::<2>(7, 0); + check::<2>(7, 1); + + check::<3>(7, 0); + check::<3>(7, 1); + check::<3>(7, 2); + } + + #[test] + fn panic_in_middle() { + check::<1>(7, 1); + check::<1>(7, 5); + check::<1>(7, 6); + + check::<2>(7, 2); + check::<2>(7, 5); + check::<2>(7, 6); + + check::<5>(13, 5); + check::<5>(13, 8); + check::<5>(13, 12); + } + + #[test] + fn len_equals_n() { + check::<1>(1, 100); + check::<1>(1, 0); + + check::<2>(2, 100); + check::<2>(2, 0); + check::<2>(2, 1); + + check::<5>(5, 100); + check::<5>(5, 0); + check::<5>(5, 1); + check::<5>(5, 4); + } +} + +#[test] +fn output_n1() { + assert_eq!("".chars().map_windows(|[c]| *c).collect::<Vec<_>>(), vec![]); + assert_eq!("x".chars().map_windows(|[c]| *c).collect::<Vec<_>>(), vec!['x']); + assert_eq!("abcd".chars().map_windows(|[c]| *c).collect::<Vec<_>>(), vec!['a', 'b', 'c', 'd']); +} + +#[test] +fn output_n2() { + assert_eq!( + "".chars().map_windows(|a: &[_; 2]| *a).collect::<Vec<_>>(), + <Vec<[char; 2]>>::new(), + ); + assert_eq!("ab".chars().map_windows(|a: &[_; 2]| *a).collect::<Vec<_>>(), vec![['a', 'b']]); + assert_eq!( + "abcd".chars().map_windows(|a: &[_; 2]| *a).collect::<Vec<_>>(), + vec![['a', 'b'], ['b', 'c'], ['c', 'd']], + ); +} + +#[test] +fn test_case_from_pr_82413_comment() { + for () in std::iter::repeat("0".to_owned()).map_windows(|_: &[_; 3]| {}).take(4) {} +} + +#[test] +#[should_panic = "array in `Iterator::map_windows` must contain more than 0 elements"] +fn check_zero_window() { + let _ = std::iter::repeat(0).map_windows(|_: &[_; 0]| ()); +} + +#[test] +fn test_zero_sized_type() { + #[derive(Copy, Clone, Debug, Eq, PartialEq)] + struct Data; + let data: Vec<_> = + std::iter::repeat(Data).take(10).map_windows(|arr: &[Data; 5]| *arr).collect(); + assert_eq!(data, [[Data; 5]; 6]); +} + +#[test] +#[should_panic = "array size of `Iterator::map_windows` is too large"] +fn test_too_large_array_size() { + let _ = std::iter::repeat(()).map_windows(|arr: &[(); usize::MAX]| *arr); +} + +#[test] +fn test_laziness() { + let counter = AtomicUsize::new(0); + let mut iter = (0..5) + .inspect(|_| { + counter.fetch_add(1, SeqCst); + }) + .map_windows(|arr: &[i32; 2]| *arr); + assert_eq!(counter.load(SeqCst), 0); + + assert_eq!(iter.next(), Some([0, 1])); + // The first iteration consumes N items (N = 2). + assert_eq!(counter.load(SeqCst), 2); + + assert_eq!(iter.next(), Some([1, 2])); + assert_eq!(counter.load(SeqCst), 3); + + assert_eq!(iter.next(), Some([2, 3])); + assert_eq!(counter.load(SeqCst), 4); + + assert_eq!(iter.next(), Some([3, 4])); + assert_eq!(counter.load(SeqCst), 5); + + assert_eq!(iter.next(), None); + assert_eq!(counter.load(SeqCst), 5); +} + +#[test] +fn test_size_hint() { + struct SizeHintCheckHelper((usize, Option<usize>)); + + impl Iterator for SizeHintCheckHelper { + type Item = i32; + + fn next(&mut self) -> Option<i32> { + let (ref mut lo, ref mut hi) = self.0; + let next = (*hi != Some(0)).then_some(0); + *lo = lo.saturating_sub(1); + if let Some(hi) = hi { + *hi = hi.saturating_sub(1); + } + next + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.0 + } + } + + fn check_size_hint<const N: usize>( + size_hint: (usize, Option<usize>), + mut mapped_size_hint: (usize, Option<usize>), + ) { + let mut iter = SizeHintCheckHelper(size_hint); + let mut mapped_iter = iter.by_ref().map_windows(|_: &[_; N]| ()); + while mapped_iter.size_hint().0 > 0 { + assert_eq!(mapped_iter.size_hint(), mapped_size_hint); + assert!(mapped_iter.next().is_some()); + mapped_size_hint.0 -= 1; + mapped_size_hint.1 = mapped_size_hint.1.map(|hi| hi.saturating_sub(1)); + } + } + + check_size_hint::<1>((0, None), (0, None)); + check_size_hint::<1>((0, Some(0)), (0, Some(0))); + check_size_hint::<1>((0, Some(2)), (0, Some(2))); + check_size_hint::<1>((1, None), (1, None)); + check_size_hint::<1>((1, Some(1)), (1, Some(1))); + check_size_hint::<1>((1, Some(4)), (1, Some(4))); + check_size_hint::<1>((5, None), (5, None)); + check_size_hint::<1>((5, Some(5)), (5, Some(5))); + check_size_hint::<1>((5, Some(10)), (5, Some(10))); + + check_size_hint::<2>((0, None), (0, None)); + check_size_hint::<2>((0, Some(0)), (0, Some(0))); + check_size_hint::<2>((0, Some(2)), (0, Some(1))); + check_size_hint::<2>((1, None), (0, None)); + check_size_hint::<2>((1, Some(1)), (0, Some(0))); + check_size_hint::<2>((1, Some(4)), (0, Some(3))); + check_size_hint::<2>((5, None), (4, None)); + check_size_hint::<2>((5, Some(5)), (4, Some(4))); + check_size_hint::<2>((5, Some(10)), (4, Some(9))); + + check_size_hint::<5>((0, None), (0, None)); + check_size_hint::<5>((0, Some(0)), (0, Some(0))); + check_size_hint::<5>((0, Some(2)), (0, Some(0))); + check_size_hint::<5>((1, None), (0, None)); + check_size_hint::<5>((1, Some(1)), (0, Some(0))); + check_size_hint::<5>((1, Some(4)), (0, Some(0))); + check_size_hint::<5>((5, None), (1, None)); + check_size_hint::<5>((5, Some(5)), (1, Some(1))); + check_size_hint::<5>((5, Some(10)), (1, Some(6))); +} |