diff options
Diffstat (limited to 'library/core/tests/iter/adapters')
22 files changed, 2596 insertions, 0 deletions
diff --git a/library/core/tests/iter/adapters/chain.rs b/library/core/tests/iter/adapters/chain.rs new file mode 100644 index 000000000..f419f9cec --- /dev/null +++ b/library/core/tests/iter/adapters/chain.rs @@ -0,0 +1,280 @@ +use super::*; +use core::iter::*; + +#[test] +fn test_iterator_chain() { + let xs = [0, 1, 2, 3, 4, 5]; + let ys = [30, 40, 50, 60]; + let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60]; + let it = xs.iter().chain(&ys); + let mut i = 0; + for &x in it { + assert_eq!(x, expected[i]); + i += 1; + } + assert_eq!(i, expected.len()); + + let ys = (30..).step_by(10).take(4); + let it = xs.iter().cloned().chain(ys); + let mut i = 0; + for x in it { + assert_eq!(x, expected[i]); + i += 1; + } + assert_eq!(i, expected.len()); +} + +#[test] +fn test_iterator_chain_advance_by() { + fn test_chain(xs: &[i32], ys: &[i32]) { + let len = xs.len() + ys.len(); + + for i in 0..xs.len() { + let mut iter = Unfuse::new(xs).chain(Unfuse::new(ys)); + iter.advance_by(i).unwrap(); + assert_eq!(iter.next(), Some(&xs[i])); + assert_eq!(iter.advance_by(100), Err(len - i - 1)); + iter.advance_by(0).unwrap(); + } + + for i in 0..ys.len() { + let mut iter = Unfuse::new(xs).chain(Unfuse::new(ys)); + iter.advance_by(xs.len() + i).unwrap(); + assert_eq!(iter.next(), Some(&ys[i])); + assert_eq!(iter.advance_by(100), Err(ys.len() - i - 1)); + iter.advance_by(0).unwrap(); + } + + let mut iter = xs.iter().chain(ys); + iter.advance_by(len).unwrap(); + assert_eq!(iter.next(), None); + iter.advance_by(0).unwrap(); + + let mut iter = xs.iter().chain(ys); + assert_eq!(iter.advance_by(len + 1), Err(len)); + iter.advance_by(0).unwrap(); + } + + test_chain(&[], &[]); + test_chain(&[], &[0, 1, 2, 3, 4, 5]); + test_chain(&[0, 1, 2, 3, 4, 5], &[]); + test_chain(&[0, 1, 2, 3, 4, 5], &[30, 40, 50, 60]); +} + +#[test] +fn test_iterator_chain_advance_back_by() { + fn test_chain(xs: &[i32], ys: &[i32]) { + let len = xs.len() + ys.len(); + + for i in 0..ys.len() { + let mut iter = Unfuse::new(xs).chain(Unfuse::new(ys)); + iter.advance_back_by(i).unwrap(); + assert_eq!(iter.next_back(), Some(&ys[ys.len() - i - 1])); + assert_eq!(iter.advance_back_by(100), Err(len - i - 1)); + iter.advance_back_by(0).unwrap(); + } + + for i in 0..xs.len() { + let mut iter = Unfuse::new(xs).chain(Unfuse::new(ys)); + iter.advance_back_by(ys.len() + i).unwrap(); + assert_eq!(iter.next_back(), Some(&xs[xs.len() - i - 1])); + assert_eq!(iter.advance_back_by(100), Err(xs.len() - i - 1)); + iter.advance_back_by(0).unwrap(); + } + + let mut iter = xs.iter().chain(ys); + iter.advance_back_by(len).unwrap(); + assert_eq!(iter.next_back(), None); + iter.advance_back_by(0).unwrap(); + + let mut iter = xs.iter().chain(ys); + assert_eq!(iter.advance_back_by(len + 1), Err(len)); + iter.advance_back_by(0).unwrap(); + } + + test_chain(&[], &[]); + test_chain(&[], &[0, 1, 2, 3, 4, 5]); + test_chain(&[0, 1, 2, 3, 4, 5], &[]); + test_chain(&[0, 1, 2, 3, 4, 5], &[30, 40, 50, 60]); +} + +#[test] +fn test_iterator_chain_nth() { + let xs = [0, 1, 2, 3, 4, 5]; + let ys = [30, 40, 50, 60]; + let zs = []; + let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60]; + for (i, x) in expected.iter().enumerate() { + assert_eq!(Some(x), xs.iter().chain(&ys).nth(i)); + } + assert_eq!(zs.iter().chain(&xs).nth(0), Some(&0)); + + let mut it = xs.iter().chain(&zs); + assert_eq!(it.nth(5), Some(&5)); + assert_eq!(it.next(), None); +} + +#[test] +fn test_iterator_chain_nth_back() { + let xs = [0, 1, 2, 3, 4, 5]; + let ys = [30, 40, 50, 60]; + let zs = []; + let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60]; + for (i, x) in expected.iter().rev().enumerate() { + assert_eq!(Some(x), xs.iter().chain(&ys).nth_back(i)); + } + assert_eq!(zs.iter().chain(&xs).nth_back(0), Some(&5)); + + let mut it = xs.iter().chain(&zs); + assert_eq!(it.nth_back(5), Some(&0)); + assert_eq!(it.next(), None); +} + +#[test] +fn test_iterator_chain_last() { + let xs = [0, 1, 2, 3, 4, 5]; + let ys = [30, 40, 50, 60]; + let zs = []; + assert_eq!(xs.iter().chain(&ys).last(), Some(&60)); + assert_eq!(zs.iter().chain(&ys).last(), Some(&60)); + assert_eq!(ys.iter().chain(&zs).last(), Some(&60)); + assert_eq!(zs.iter().chain(&zs).last(), None); +} + +#[test] +fn test_iterator_chain_count() { + let xs = [0, 1, 2, 3, 4, 5]; + let ys = [30, 40, 50, 60]; + let zs = []; + assert_eq!(xs.iter().chain(&ys).count(), 10); + assert_eq!(zs.iter().chain(&ys).count(), 4); +} + +#[test] +fn test_iterator_chain_find() { + let xs = [0, 1, 2, 3, 4, 5]; + let ys = [30, 40, 50, 60]; + let mut iter = xs.iter().chain(&ys); + assert_eq!(iter.find(|&&i| i == 4), Some(&4)); + assert_eq!(iter.next(), Some(&5)); + assert_eq!(iter.find(|&&i| i == 40), Some(&40)); + assert_eq!(iter.next(), Some(&50)); + assert_eq!(iter.find(|&&i| i == 100), None); + assert_eq!(iter.next(), None); +} + +#[test] +fn test_iterator_chain_size_hint() { + // this chains an iterator of length 0 with an iterator of length 1, + // so after calling `.next()` once, the iterator is empty and the + // state is `ChainState::Back`. `.size_hint()` should now disregard + // the size hint of the left iterator + let mut iter = Toggle { is_empty: true }.chain(once(())); + assert_eq!(iter.next(), Some(())); + assert_eq!(iter.size_hint(), (0, Some(0))); + + let mut iter = once(()).chain(Toggle { is_empty: true }); + assert_eq!(iter.next_back(), Some(())); + assert_eq!(iter.size_hint(), (0, Some(0))); +} + +#[test] +fn test_iterator_chain_unfused() { + // Chain shouldn't be fused in its second iterator, depending on direction + let mut iter = NonFused::new(empty()).chain(Toggle { is_empty: true }); + assert!(iter.next().is_none()); + assert!(iter.next().is_some()); + assert!(iter.next().is_none()); + + let mut iter = Toggle { is_empty: true }.chain(NonFused::new(empty())); + assert!(iter.next_back().is_none()); + assert!(iter.next_back().is_some()); + assert!(iter.next_back().is_none()); +} + +#[test] +fn test_chain_fold() { + let xs = [1, 2, 3]; + let ys = [1, 2, 0]; + + let mut iter = xs.iter().chain(&ys); + iter.next(); + let mut result = Vec::new(); + iter.fold((), |(), &elt| result.push(elt)); + assert_eq!(&[2, 3, 1, 2, 0], &result[..]); +} + +#[test] +fn test_chain_try_folds() { + let c = || (0..10).chain(10..20); + + let f = &|acc, x| i32::checked_add(2 * acc, x); + assert_eq!(c().try_fold(7, f), (0..20).try_fold(7, f)); + assert_eq!(c().try_rfold(7, f), (0..20).rev().try_fold(7, f)); + + let mut iter = c(); + assert_eq!(iter.position(|x| x == 5), Some(5)); + assert_eq!(iter.next(), Some(6), "stopped in front, state Both"); + assert_eq!(iter.position(|x| x == 13), Some(6)); + assert_eq!(iter.next(), Some(14), "stopped in back, state Back"); + assert_eq!(iter.try_fold(0, |acc, x| Some(acc + x)), Some((15..20).sum())); + + let mut iter = c().rev(); // use rev to access try_rfold + assert_eq!(iter.position(|x| x == 15), Some(4)); + assert_eq!(iter.next(), Some(14), "stopped in back, state Both"); + assert_eq!(iter.position(|x| x == 5), Some(8)); + assert_eq!(iter.next(), Some(4), "stopped in front, state Front"); + assert_eq!(iter.try_fold(0, |acc, x| Some(acc + x)), Some((0..4).sum())); + + let mut iter = c(); + iter.by_ref().rev().nth(14); // skip the last 15, ending in state Front + assert_eq!(iter.try_fold(7, f), (0..5).try_fold(7, f)); + + let mut iter = c(); + iter.nth(14); // skip the first 15, ending in state Back + assert_eq!(iter.try_rfold(7, f), (15..20).try_rfold(7, f)); +} + +#[test] +fn test_double_ended_chain() { + let xs = [1, 2, 3, 4, 5]; + let ys = [7, 9, 11]; + let mut it = xs.iter().chain(&ys).rev(); + assert_eq!(it.next().unwrap(), &11); + assert_eq!(it.next().unwrap(), &9); + assert_eq!(it.next_back().unwrap(), &1); + assert_eq!(it.next_back().unwrap(), &2); + assert_eq!(it.next_back().unwrap(), &3); + assert_eq!(it.next_back().unwrap(), &4); + assert_eq!(it.next_back().unwrap(), &5); + assert_eq!(it.next_back().unwrap(), &7); + assert_eq!(it.next_back(), None); + + // test that .chain() is well behaved with an unfused iterator + struct CrazyIterator(bool); + impl CrazyIterator { + fn new() -> CrazyIterator { + CrazyIterator(false) + } + } + impl Iterator for CrazyIterator { + type Item = i32; + fn next(&mut self) -> Option<i32> { + if self.0 { + Some(99) + } else { + self.0 = true; + None + } + } + } + + impl DoubleEndedIterator for CrazyIterator { + fn next_back(&mut self) -> Option<i32> { + self.next() + } + } + + assert_eq!(CrazyIterator::new().chain(0..10).rev().last(), Some(0)); + assert!((0..10).chain(CrazyIterator::new()).rev().any(|i| i == 0)); +} diff --git a/library/core/tests/iter/adapters/cloned.rs b/library/core/tests/iter/adapters/cloned.rs new file mode 100644 index 000000000..78babb7fe --- /dev/null +++ b/library/core/tests/iter/adapters/cloned.rs @@ -0,0 +1,52 @@ +use core::iter::*; + +#[test] +fn test_cloned() { + let xs = [2, 4, 6, 8]; + + let mut it = xs.iter().cloned(); + assert_eq!(it.len(), 4); + assert_eq!(it.next(), Some(2)); + assert_eq!(it.len(), 3); + assert_eq!(it.next(), Some(4)); + assert_eq!(it.len(), 2); + assert_eq!(it.next_back(), Some(8)); + assert_eq!(it.len(), 1); + assert_eq!(it.next_back(), Some(6)); + assert_eq!(it.len(), 0); + assert_eq!(it.next_back(), None); +} + +#[test] +fn test_cloned_side_effects() { + let mut count = 0; + { + let iter = [1, 2, 3] + .iter() + .map(|x| { + count += 1; + x + }) + .cloned() + .zip(&[1]); + for _ in iter {} + } + assert_eq!(count, 2); +} + +#[test] +fn test_cloned_try_folds() { + let a = [1, 2, 3, 4, 5, 6, 7, 8, 9]; + let f = &|acc, x| i32::checked_add(2 * acc, x); + let f_ref = &|acc, &x| i32::checked_add(2 * acc, x); + assert_eq!(a.iter().cloned().try_fold(7, f), a.iter().try_fold(7, f_ref)); + assert_eq!(a.iter().cloned().try_rfold(7, f), a.iter().try_rfold(7, f_ref)); + + let a = [10, 20, 30, 40, 100, 60, 70, 80, 90]; + let mut iter = a.iter().cloned(); + assert_eq!(iter.try_fold(0_i8, |acc, x| acc.checked_add(x)), None); + assert_eq!(iter.next(), Some(60)); + let mut iter = a.iter().cloned(); + assert_eq!(iter.try_rfold(0_i8, |acc, x| acc.checked_add(x)), None); + assert_eq!(iter.next_back(), Some(70)); +} diff --git a/library/core/tests/iter/adapters/copied.rs b/library/core/tests/iter/adapters/copied.rs new file mode 100644 index 000000000..b12f2035d --- /dev/null +++ b/library/core/tests/iter/adapters/copied.rs @@ -0,0 +1,18 @@ +use core::iter::*; + +#[test] +fn test_copied() { + let xs = [2, 4, 6, 8]; + + let mut it = xs.iter().copied(); + assert_eq!(it.len(), 4); + assert_eq!(it.next(), Some(2)); + assert_eq!(it.len(), 3); + assert_eq!(it.next(), Some(4)); + assert_eq!(it.len(), 2); + assert_eq!(it.next_back(), Some(8)); + assert_eq!(it.len(), 1); + assert_eq!(it.next_back(), Some(6)); + assert_eq!(it.len(), 0); + assert_eq!(it.next_back(), None); +} diff --git a/library/core/tests/iter/adapters/cycle.rs b/library/core/tests/iter/adapters/cycle.rs new file mode 100644 index 000000000..8831c09b4 --- /dev/null +++ b/library/core/tests/iter/adapters/cycle.rs @@ -0,0 +1,31 @@ +use core::iter::*; + +#[test] +fn test_cycle() { + let cycle_len = 3; + let it = (0..).step_by(1).take(cycle_len).cycle(); + assert_eq!(it.size_hint(), (usize::MAX, None)); + for (i, x) in it.take(100).enumerate() { + assert_eq!(i % cycle_len, x); + } + + let mut it = (0..).step_by(1).take(0).cycle(); + assert_eq!(it.size_hint(), (0, Some(0))); + assert_eq!(it.next(), None); + + assert_eq!(empty::<i32>().cycle().fold(0, |acc, x| acc + x), 0); + + assert_eq!(once(1).cycle().skip(1).take(4).fold(0, |acc, x| acc + x), 4); + + assert_eq!((0..10).cycle().take(5).sum::<i32>(), 10); + assert_eq!((0..10).cycle().take(15).sum::<i32>(), 55); + assert_eq!((0..10).cycle().take(25).sum::<i32>(), 100); + + let mut iter = (0..10).cycle(); + iter.nth(14); + assert_eq!(iter.take(8).sum::<i32>(), 38); + + let mut iter = (0..10).cycle(); + iter.nth(9); + assert_eq!(iter.take(3).sum::<i32>(), 3); +} 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); +} diff --git a/library/core/tests/iter/adapters/filter.rs b/library/core/tests/iter/adapters/filter.rs new file mode 100644 index 000000000..a2050d89d --- /dev/null +++ b/library/core/tests/iter/adapters/filter.rs @@ -0,0 +1,52 @@ +use core::iter::*; + +#[test] +fn test_iterator_filter_count() { + let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8]; + assert_eq!(xs.iter().filter(|&&x| x % 2 == 0).count(), 5); +} + +#[test] +fn test_iterator_filter_fold() { + let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8]; + let ys = [0, 2, 4, 6, 8]; + let it = xs.iter().filter(|&&x| x % 2 == 0); + let i = it.fold(0, |i, &x| { + assert_eq!(x, ys[i]); + i + 1 + }); + assert_eq!(i, ys.len()); + + let it = xs.iter().filter(|&&x| x % 2 == 0); + let i = it.rfold(ys.len(), |i, &x| { + assert_eq!(x, ys[i - 1]); + i - 1 + }); + assert_eq!(i, 0); +} + +#[test] +fn test_filter_try_folds() { + fn p(&x: &i32) -> bool { + 0 <= x && x < 10 + } + let f = &|acc, x| i32::checked_add(2 * acc, x); + assert_eq!((-10..20).filter(p).try_fold(7, f), (0..10).try_fold(7, f)); + assert_eq!((-10..20).filter(p).try_rfold(7, f), (0..10).try_rfold(7, f)); + + let mut iter = (0..40).filter(|&x| x % 2 == 1); + assert_eq!(iter.try_fold(0, i8::checked_add), None); + assert_eq!(iter.next(), Some(25)); + assert_eq!(iter.try_rfold(0, i8::checked_add), None); + assert_eq!(iter.next_back(), Some(31)); +} + +#[test] +fn test_double_ended_filter() { + let xs = [1, 2, 3, 4, 5, 6]; + let mut it = xs.iter().filter(|&x| *x & 1 == 0); + assert_eq!(it.next_back().unwrap(), &6); + assert_eq!(it.next_back().unwrap(), &4); + assert_eq!(it.next().unwrap(), &2); + assert_eq!(it.next_back(), None); +} diff --git a/library/core/tests/iter/adapters/filter_map.rs b/library/core/tests/iter/adapters/filter_map.rs new file mode 100644 index 000000000..46738eda6 --- /dev/null +++ b/library/core/tests/iter/adapters/filter_map.rs @@ -0,0 +1,50 @@ +use core::iter::*; + +#[test] +fn test_filter_map() { + let it = (0..).step_by(1).take(10).filter_map(|x| if x % 2 == 0 { Some(x * x) } else { None }); + assert_eq!(it.collect::<Vec<usize>>(), [0 * 0, 2 * 2, 4 * 4, 6 * 6, 8 * 8]); +} + +#[test] +fn test_filter_map_fold() { + let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8]; + let ys = [0 * 0, 2 * 2, 4 * 4, 6 * 6, 8 * 8]; + let it = xs.iter().filter_map(|&x| if x % 2 == 0 { Some(x * x) } else { None }); + let i = it.fold(0, |i, x| { + assert_eq!(x, ys[i]); + i + 1 + }); + assert_eq!(i, ys.len()); + + let it = xs.iter().filter_map(|&x| if x % 2 == 0 { Some(x * x) } else { None }); + let i = it.rfold(ys.len(), |i, x| { + assert_eq!(x, ys[i - 1]); + i - 1 + }); + assert_eq!(i, 0); +} + +#[test] +fn test_filter_map_try_folds() { + let mp = &|x| if 0 <= x && x < 10 { Some(x * 2) } else { None }; + let f = &|acc, x| i32::checked_add(2 * acc, x); + assert_eq!((-9..20).filter_map(mp).try_fold(7, f), (0..10).map(|x| 2 * x).try_fold(7, f)); + assert_eq!((-9..20).filter_map(mp).try_rfold(7, f), (0..10).map(|x| 2 * x).try_rfold(7, f)); + + let mut iter = (0..40).filter_map(|x| if x % 2 == 1 { None } else { Some(x * 2 + 10) }); + assert_eq!(iter.try_fold(0, i8::checked_add), None); + assert_eq!(iter.next(), Some(38)); + assert_eq!(iter.try_rfold(0, i8::checked_add), None); + assert_eq!(iter.next_back(), Some(78)); +} + +#[test] +fn test_double_ended_filter_map() { + let xs = [1, 2, 3, 4, 5, 6]; + let mut it = xs.iter().filter_map(|&x| if x & 1 == 0 { Some(x * 2) } else { None }); + assert_eq!(it.next_back().unwrap(), 12); + assert_eq!(it.next_back().unwrap(), 8); + assert_eq!(it.next().unwrap(), 4); + assert_eq!(it.next_back(), None); +} 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); +} 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))); +} diff --git a/library/core/tests/iter/adapters/fuse.rs b/library/core/tests/iter/adapters/fuse.rs new file mode 100644 index 000000000..f41b379b3 --- /dev/null +++ b/library/core/tests/iter/adapters/fuse.rs @@ -0,0 +1,75 @@ +use core::iter::*; + +#[test] +fn test_fuse_nth() { + let xs = [0, 1, 2]; + let mut it = xs.iter(); + + assert_eq!(it.len(), 3); + assert_eq!(it.nth(2), Some(&2)); + assert_eq!(it.len(), 0); + assert_eq!(it.nth(2), None); + assert_eq!(it.len(), 0); +} + +#[test] +fn test_fuse_last() { + let xs = [0, 1, 2]; + let it = xs.iter(); + + assert_eq!(it.len(), 3); + assert_eq!(it.last(), Some(&2)); +} + +#[test] +fn test_fuse_count() { + let xs = [0, 1, 2]; + let it = xs.iter(); + + assert_eq!(it.len(), 3); + assert_eq!(it.count(), 3); + // Can't check len now because count consumes. +} + +#[test] +fn test_fuse_fold() { + let xs = [0, 1, 2]; + let it = xs.iter(); // `FusedIterator` + let i = it.fuse().fold(0, |i, &x| { + assert_eq!(x, xs[i]); + i + 1 + }); + assert_eq!(i, xs.len()); + + let it = xs.iter(); // `FusedIterator` + let i = it.fuse().rfold(xs.len(), |i, &x| { + assert_eq!(x, xs[i - 1]); + i - 1 + }); + assert_eq!(i, 0); + + let it = xs.iter().scan((), |_, &x| Some(x)); // `!FusedIterator` + let i = it.fuse().fold(0, |i, x| { + assert_eq!(x, xs[i]); + i + 1 + }); + assert_eq!(i, xs.len()); +} + +#[test] +fn test_fuse() { + let mut it = 0..3; + assert_eq!(it.len(), 3); + assert_eq!(it.next(), Some(0)); + assert_eq!(it.len(), 2); + assert_eq!(it.next(), Some(1)); + assert_eq!(it.len(), 1); + assert_eq!(it.next(), Some(2)); + assert_eq!(it.len(), 0); + assert_eq!(it.next(), None); + assert_eq!(it.len(), 0); + assert_eq!(it.next(), None); + assert_eq!(it.len(), 0); + assert_eq!(it.next(), None); + assert_eq!(it.len(), 0); +} diff --git a/library/core/tests/iter/adapters/inspect.rs b/library/core/tests/iter/adapters/inspect.rs new file mode 100644 index 000000000..939e3a28a --- /dev/null +++ b/library/core/tests/iter/adapters/inspect.rs @@ -0,0 +1,38 @@ +use core::iter::*; + +#[test] +fn test_inspect() { + let xs = [1, 2, 3, 4]; + let mut n = 0; + + let ys = xs.iter().cloned().inspect(|_| n += 1).collect::<Vec<usize>>(); + + assert_eq!(n, xs.len()); + assert_eq!(&xs[..], &ys[..]); +} + +#[test] +fn test_inspect_fold() { + let xs = [1, 2, 3, 4]; + let mut n = 0; + { + let it = xs.iter().inspect(|_| n += 1); + let i = it.fold(0, |i, &x| { + assert_eq!(x, xs[i]); + i + 1 + }); + assert_eq!(i, xs.len()); + } + assert_eq!(n, xs.len()); + + let mut n = 0; + { + let it = xs.iter().inspect(|_| n += 1); + let i = it.rfold(xs.len(), |i, &x| { + assert_eq!(x, xs[i - 1]); + i - 1 + }); + assert_eq!(i, 0); + } + assert_eq!(n, xs.len()); +} diff --git a/library/core/tests/iter/adapters/intersperse.rs b/library/core/tests/iter/adapters/intersperse.rs new file mode 100644 index 000000000..72ae59b6b --- /dev/null +++ b/library/core/tests/iter/adapters/intersperse.rs @@ -0,0 +1,154 @@ +use core::iter::*; + +#[test] +fn test_intersperse() { + let v = std::iter::empty().intersperse(0u32).collect::<Vec<_>>(); + assert_eq!(v, vec![]); + + let v = std::iter::once(1).intersperse(0).collect::<Vec<_>>(); + assert_eq!(v, vec![1]); + + let xs = ["a", "", "b", "c"]; + let v: Vec<&str> = xs.iter().map(|x| *x).intersperse(", ").collect(); + let text: String = v.concat(); + assert_eq!(text, "a, , b, c".to_string()); + + let ys = [0, 1, 2, 3]; + let mut it = ys[..0].iter().map(|x| *x).intersperse(1); + assert!(it.next() == None); +} + +#[test] +fn test_intersperse_size_hint() { + let iter = std::iter::empty::<i32>().intersperse(0); + assert_eq!(iter.size_hint(), (0, Some(0))); + + let xs = ["a", "", "b", "c"]; + let mut iter = xs.iter().map(|x| *x).intersperse(", "); + assert_eq!(iter.size_hint(), (7, Some(7))); + + assert_eq!(iter.next(), Some("a")); + assert_eq!(iter.size_hint(), (6, Some(6))); + assert_eq!(iter.next(), Some(", ")); + assert_eq!(iter.size_hint(), (5, Some(5))); + + assert_eq!([].iter().intersperse(&()).size_hint(), (0, Some(0))); +} + +#[test] +fn test_fold_specialization_intersperse() { + let mut iter = (1..2).intersperse(0); + iter.clone().for_each(|x| assert_eq!(Some(x), iter.next())); + + let mut iter = (1..3).intersperse(0); + iter.clone().for_each(|x| assert_eq!(Some(x), iter.next())); + + let mut iter = (1..4).intersperse(0); + iter.clone().for_each(|x| assert_eq!(Some(x), iter.next())); +} + +#[test] +fn test_try_fold_specialization_intersperse_ok() { + let mut iter = (1..2).intersperse(0); + iter.clone().try_for_each(|x| { + assert_eq!(Some(x), iter.next()); + Some(()) + }); + + let mut iter = (1..3).intersperse(0); + iter.clone().try_for_each(|x| { + assert_eq!(Some(x), iter.next()); + Some(()) + }); + + let mut iter = (1..4).intersperse(0); + iter.clone().try_for_each(|x| { + assert_eq!(Some(x), iter.next()); + Some(()) + }); +} + +#[test] +fn test_intersperse_with() { + #[derive(PartialEq, Debug)] + struct NotClone { + u: u32, + } + let r = [NotClone { u: 0 }, NotClone { u: 1 }] + .into_iter() + .intersperse_with(|| NotClone { u: 2 }) + .collect::<Vec<_>>(); + assert_eq!(r, vec![NotClone { u: 0 }, NotClone { u: 2 }, NotClone { u: 1 }]); + + let mut ctr = 100; + let separator = || { + ctr *= 2; + ctr + }; + let r = (0..3).intersperse_with(separator).collect::<Vec<_>>(); + assert_eq!(r, vec![0, 200, 1, 400, 2]); +} + +#[test] +fn test_intersperse_fold() { + let v = (1..4).intersperse(9).fold(Vec::new(), |mut acc, x| { + acc.push(x); + acc + }); + assert_eq!(v.as_slice(), [1, 9, 2, 9, 3]); + + let mut iter = (1..4).intersperse(9); + assert_eq!(iter.next(), Some(1)); + let v = iter.fold(Vec::new(), |mut acc, x| { + acc.push(x); + acc + }); + assert_eq!(v.as_slice(), [9, 2, 9, 3]); + + struct NoneAtStart(i32); // Produces: None, Some(2), Some(3), None, ... + impl Iterator for NoneAtStart { + type Item = i32; + fn next(&mut self) -> Option<i32> { + self.0 += 1; + Some(self.0).filter(|i| i % 3 != 1) + } + } + + let v = NoneAtStart(0).intersperse(1000).fold(0, |a, b| a + b); + assert_eq!(v, 0); +} + +#[test] +fn test_intersperse_collect_string() { + let contents = [1, 2, 3]; + + let contents_string = contents + .into_iter() + .map(|id| id.to_string()) + .intersperse(", ".to_owned()) + .collect::<String>(); + assert_eq!(contents_string, "1, 2, 3"); +} + +#[test] +fn test_try_fold_specialization_intersperse_err() { + let orig_iter = ["a", "b"].iter().copied().intersperse("-"); + + // Abort after the first item. + let mut iter = orig_iter.clone(); + iter.try_for_each(|_| None::<()>); + assert_eq!(iter.next(), Some("-")); + assert_eq!(iter.next(), Some("b")); + assert_eq!(iter.next(), None); + + // Abort after the second item. + let mut iter = orig_iter.clone(); + iter.try_for_each(|item| if item == "-" { None } else { Some(()) }); + assert_eq!(iter.next(), Some("b")); + assert_eq!(iter.next(), None); + + // Abort after the third item. + let mut iter = orig_iter.clone(); + iter.try_for_each(|item| if item == "b" { None } else { Some(()) }); + assert_eq!(iter.next(), None); +} diff --git a/library/core/tests/iter/adapters/map.rs b/library/core/tests/iter/adapters/map.rs new file mode 100644 index 000000000..77ce3819b --- /dev/null +++ b/library/core/tests/iter/adapters/map.rs @@ -0,0 +1,27 @@ +use core::iter::*; + +#[test] +fn test_map_try_folds() { + let f = &|acc, x| i32::checked_add(2 * acc, x); + assert_eq!((0..10).map(|x| x + 3).try_fold(7, f), (3..13).try_fold(7, f)); + assert_eq!((0..10).map(|x| x + 3).try_rfold(7, f), (3..13).try_rfold(7, f)); + + let mut iter = (0..40).map(|x| x + 10); + assert_eq!(iter.try_fold(0, i8::checked_add), None); + assert_eq!(iter.next(), Some(20)); + assert_eq!(iter.try_rfold(0, i8::checked_add), None); + assert_eq!(iter.next_back(), Some(46)); +} + +#[test] +fn test_double_ended_map() { + let xs = [1, 2, 3, 4, 5, 6]; + let mut it = xs.iter().map(|&x| x * -1); + assert_eq!(it.next(), Some(-1)); + assert_eq!(it.next(), Some(-2)); + assert_eq!(it.next_back(), Some(-6)); + assert_eq!(it.next_back(), Some(-5)); + assert_eq!(it.next(), Some(-3)); + assert_eq!(it.next_back(), Some(-4)); + assert_eq!(it.next(), None); +} diff --git a/library/core/tests/iter/adapters/mod.rs b/library/core/tests/iter/adapters/mod.rs new file mode 100644 index 000000000..567d9fe49 --- /dev/null +++ b/library/core/tests/iter/adapters/mod.rs @@ -0,0 +1,185 @@ +mod chain; +mod cloned; +mod copied; +mod cycle; +mod enumerate; +mod filter; +mod filter_map; +mod flat_map; +mod flatten; +mod fuse; +mod inspect; +mod intersperse; +mod map; +mod peekable; +mod scan; +mod skip; +mod skip_while; +mod step_by; +mod take; +mod take_while; +mod zip; + +use core::cell::Cell; + +/// An iterator that panics whenever `next` or next_back` is called +/// after `None` has already been returned. This does not violate +/// `Iterator`'s contract. Used to test that iterator adapters don't +/// poll their inner iterators after exhausting them. +pub struct NonFused<I> { + iter: I, + done: bool, +} + +impl<I> NonFused<I> { + pub fn new(iter: I) -> Self { + Self { iter, done: false } + } +} + +impl<I> Iterator for NonFused<I> +where + I: Iterator, +{ + type Item = I::Item; + + fn next(&mut self) -> Option<Self::Item> { + assert!(!self.done, "this iterator has already returned None"); + self.iter.next().or_else(|| { + self.done = true; + None + }) + } +} + +impl<I> DoubleEndedIterator for NonFused<I> +where + I: DoubleEndedIterator, +{ + fn next_back(&mut self) -> Option<Self::Item> { + assert!(!self.done, "this iterator has already returned None"); + self.iter.next_back().or_else(|| { + self.done = true; + None + }) + } +} + +/// An iterator wrapper that panics whenever `next` or `next_back` is called +/// after `None` has been returned. +pub struct Unfuse<I> { + iter: I, + exhausted: bool, +} + +impl<I> Unfuse<I> { + pub fn new<T>(iter: T) -> Self + where + T: IntoIterator<IntoIter = I>, + { + Self { iter: iter.into_iter(), exhausted: false } + } +} + +impl<I> Iterator for Unfuse<I> +where + I: Iterator, +{ + type Item = I::Item; + + fn next(&mut self) -> Option<Self::Item> { + assert!(!self.exhausted); + let next = self.iter.next(); + self.exhausted = next.is_none(); + next + } +} + +impl<I> DoubleEndedIterator for Unfuse<I> +where + I: DoubleEndedIterator, +{ + fn next_back(&mut self) -> Option<Self::Item> { + assert!(!self.exhausted); + let next = self.iter.next_back(); + self.exhausted = next.is_none(); + next + } +} + +pub struct Toggle { + is_empty: bool, +} + +impl Iterator for Toggle { + type Item = (); + + // alternates between `None` and `Some(())` + fn next(&mut self) -> Option<Self::Item> { + if self.is_empty { + self.is_empty = false; + None + } else { + self.is_empty = true; + Some(()) + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.is_empty { (0, Some(0)) } else { (1, Some(1)) } + } +} + +impl DoubleEndedIterator for Toggle { + fn next_back(&mut self) -> Option<Self::Item> { + self.next() + } +} + +/// This is an iterator that follows the Iterator contract, +/// but it is not fused. After having returned None once, it will start +/// producing elements if .next() is called again. +pub struct CycleIter<'a, T> { + index: usize, + data: &'a [T], +} + +impl<'a, T> CycleIter<'a, T> { + pub fn new(data: &'a [T]) -> Self { + Self { index: 0, data } + } +} + +impl<'a, T> Iterator for CycleIter<'a, T> { + type Item = &'a T; + fn next(&mut self) -> Option<Self::Item> { + let elt = self.data.get(self.index); + self.index += 1; + self.index %= 1 + self.data.len(); + elt + } +} + +#[derive(Debug)] +struct CountClone(Cell<i32>); + +impl CountClone { + pub fn new() -> Self { + Self(Cell::new(0)) + } +} + +impl PartialEq<i32> for CountClone { + fn eq(&self, rhs: &i32) -> bool { + self.0.get() == *rhs + } +} + +impl Clone for CountClone { + fn clone(&self) -> Self { + let ret = CountClone(self.0.clone()); + let n = self.0.get(); + self.0.set(n + 1); + ret + } +} diff --git a/library/core/tests/iter/adapters/peekable.rs b/library/core/tests/iter/adapters/peekable.rs new file mode 100644 index 000000000..c1a1c29b6 --- /dev/null +++ b/library/core/tests/iter/adapters/peekable.rs @@ -0,0 +1,272 @@ +use super::*; +use core::iter::*; + +#[test] +fn test_iterator_peekable() { + let xs = vec![0, 1, 2, 3, 4, 5]; + + let mut it = xs.iter().cloned().peekable(); + assert_eq!(it.len(), 6); + assert_eq!(it.peek().unwrap(), &0); + assert_eq!(it.len(), 6); + assert_eq!(it.next().unwrap(), 0); + assert_eq!(it.len(), 5); + assert_eq!(it.next().unwrap(), 1); + assert_eq!(it.len(), 4); + assert_eq!(it.next().unwrap(), 2); + assert_eq!(it.len(), 3); + assert_eq!(it.peek().unwrap(), &3); + assert_eq!(it.len(), 3); + assert_eq!(it.peek().unwrap(), &3); + assert_eq!(it.len(), 3); + assert_eq!(it.next().unwrap(), 3); + assert_eq!(it.len(), 2); + assert_eq!(it.next().unwrap(), 4); + assert_eq!(it.len(), 1); + assert_eq!(it.peek().unwrap(), &5); + assert_eq!(it.len(), 1); + assert_eq!(it.next().unwrap(), 5); + assert_eq!(it.len(), 0); + assert!(it.peek().is_none()); + assert_eq!(it.len(), 0); + assert!(it.next().is_none()); + assert_eq!(it.len(), 0); + + let mut it = xs.iter().cloned().peekable(); + assert_eq!(it.len(), 6); + assert_eq!(it.peek().unwrap(), &0); + assert_eq!(it.len(), 6); + assert_eq!(it.next_back().unwrap(), 5); + assert_eq!(it.len(), 5); + assert_eq!(it.next_back().unwrap(), 4); + assert_eq!(it.len(), 4); + assert_eq!(it.next_back().unwrap(), 3); + assert_eq!(it.len(), 3); + assert_eq!(it.peek().unwrap(), &0); + assert_eq!(it.len(), 3); + assert_eq!(it.peek().unwrap(), &0); + assert_eq!(it.len(), 3); + assert_eq!(it.next_back().unwrap(), 2); + assert_eq!(it.len(), 2); + assert_eq!(it.next_back().unwrap(), 1); + assert_eq!(it.len(), 1); + assert_eq!(it.peek().unwrap(), &0); + assert_eq!(it.len(), 1); + assert_eq!(it.next_back().unwrap(), 0); + assert_eq!(it.len(), 0); + assert!(it.peek().is_none()); + assert_eq!(it.len(), 0); + assert!(it.next_back().is_none()); + assert_eq!(it.len(), 0); +} + +#[test] +fn test_iterator_peekable_count() { + let xs = [0, 1, 2, 3, 4, 5]; + let ys = [10]; + let zs: [i32; 0] = []; + + assert_eq!(xs.iter().peekable().count(), 6); + + let mut it = xs.iter().peekable(); + assert_eq!(it.peek(), Some(&&0)); + assert_eq!(it.count(), 6); + + assert_eq!(ys.iter().peekable().count(), 1); + + let mut it = ys.iter().peekable(); + assert_eq!(it.peek(), Some(&&10)); + assert_eq!(it.count(), 1); + + assert_eq!(zs.iter().peekable().count(), 0); + + let mut it = zs.iter().peekable(); + assert_eq!(it.peek(), None); +} + +#[test] +fn test_iterator_peekable_nth() { + let xs = [0, 1, 2, 3, 4, 5]; + let mut it = xs.iter().peekable(); + + assert_eq!(it.peek(), Some(&&0)); + assert_eq!(it.nth(0), Some(&0)); + assert_eq!(it.peek(), Some(&&1)); + assert_eq!(it.nth(1), Some(&2)); + assert_eq!(it.peek(), Some(&&3)); + assert_eq!(it.nth(2), Some(&5)); + assert_eq!(it.next(), None); +} + +#[test] +fn test_iterator_peekable_last() { + let xs = [0, 1, 2, 3, 4, 5]; + let ys = [0]; + + let mut it = xs.iter().peekable(); + assert_eq!(it.peek(), Some(&&0)); + assert_eq!(it.last(), Some(&5)); + + let mut it = ys.iter().peekable(); + assert_eq!(it.peek(), Some(&&0)); + assert_eq!(it.last(), Some(&0)); + + let mut it = ys.iter().peekable(); + assert_eq!(it.next(), Some(&0)); + assert_eq!(it.peek(), None); + assert_eq!(it.last(), None); +} + +#[test] +fn test_iterator_peekable_fold() { + let xs = [0, 1, 2, 3, 4, 5]; + let mut it = xs.iter().peekable(); + assert_eq!(it.peek(), Some(&&0)); + let i = it.fold(0, |i, &x| { + assert_eq!(x, xs[i]); + i + 1 + }); + assert_eq!(i, xs.len()); +} + +#[test] +fn test_iterator_peekable_rfold() { + let xs = [0, 1, 2, 3, 4, 5]; + let mut it = xs.iter().peekable(); + assert_eq!(it.peek(), Some(&&0)); + let i = it.rfold(0, |i, &x| { + assert_eq!(x, xs[xs.len() - 1 - i]); + i + 1 + }); + assert_eq!(i, xs.len()); +} + +#[test] +fn test_iterator_peekable_next_if_eq() { + // first, try on references + let xs = ["Heart", "of", "Gold"]; + let mut it = xs.into_iter().peekable(); + // try before `peek()` + assert_eq!(it.next_if_eq(&"trillian"), None); + assert_eq!(it.next_if_eq(&"Heart"), Some("Heart")); + // try after peek() + assert_eq!(it.peek(), Some(&"of")); + assert_eq!(it.next_if_eq(&"of"), Some("of")); + assert_eq!(it.next_if_eq(&"zaphod"), None); + // make sure `next()` still behaves + assert_eq!(it.next(), Some("Gold")); + + // make sure comparison works for owned values + let xs = [String::from("Ludicrous"), "speed".into()]; + let mut it = xs.into_iter().peekable(); + // make sure basic functionality works + assert_eq!(it.next_if_eq("Ludicrous"), Some("Ludicrous".into())); + assert_eq!(it.next_if_eq("speed"), Some("speed".into())); + assert_eq!(it.next_if_eq(""), None); +} + +#[test] +fn test_iterator_peekable_mut() { + let mut it = [1, 2, 3].into_iter().peekable(); + if let Some(p) = it.peek_mut() { + if *p == 1 { + *p = 5; + } + } + assert_eq!(it.collect::<Vec<_>>(), vec![5, 2, 3]); +} + +#[test] +fn test_iterator_peekable_remember_peek_none_1() { + // Check that the loop using .peek() terminates + let data = [1, 2, 3]; + let mut iter = CycleIter::new(&data).peekable(); + + let mut n = 0; + while let Some(_) = iter.next() { + let is_the_last = iter.peek().is_none(); + assert_eq!(is_the_last, n == data.len() - 1); + n += 1; + if n > data.len() { + break; + } + } + assert_eq!(n, data.len()); +} + +#[test] +fn test_iterator_peekable_remember_peek_none_2() { + let data = [0]; + let mut iter = CycleIter::new(&data).peekable(); + iter.next(); + assert_eq!(iter.peek(), None); + assert_eq!(iter.last(), None); +} + +#[test] +fn test_iterator_peekable_remember_peek_none_3() { + let data = [0]; + let mut iter = CycleIter::new(&data).peekable(); + iter.peek(); + assert_eq!(iter.nth(0), Some(&0)); + + let mut iter = CycleIter::new(&data).peekable(); + iter.next(); + assert_eq!(iter.peek(), None); + assert_eq!(iter.nth(0), None); +} + +#[test] +fn test_peek_try_folds() { + let f = &|acc, x| i32::checked_add(2 * acc, x); + + assert_eq!((1..20).peekable().try_fold(7, f), (1..20).try_fold(7, f)); + assert_eq!((1..20).peekable().try_rfold(7, f), (1..20).try_rfold(7, f)); + + let mut iter = (1..20).peekable(); + assert_eq!(iter.peek(), Some(&1)); + assert_eq!(iter.try_fold(7, f), (1..20).try_fold(7, f)); + + let mut iter = (1..20).peekable(); + assert_eq!(iter.peek(), Some(&1)); + assert_eq!(iter.try_rfold(7, f), (1..20).try_rfold(7, f)); + + let mut iter = [100, 20, 30, 40, 50, 60, 70].iter().cloned().peekable(); + assert_eq!(iter.peek(), Some(&100)); + assert_eq!(iter.try_fold(0, i8::checked_add), None); + assert_eq!(iter.peek(), Some(&40)); + + let mut iter = [100, 20, 30, 40, 50, 60, 70].iter().cloned().peekable(); + assert_eq!(iter.peek(), Some(&100)); + assert_eq!(iter.try_rfold(0, i8::checked_add), None); + assert_eq!(iter.peek(), Some(&100)); + assert_eq!(iter.next_back(), Some(50)); + + let mut iter = (2..5).peekable(); + assert_eq!(iter.peek(), Some(&2)); + assert_eq!(iter.try_for_each(Err), Err(2)); + assert_eq!(iter.peek(), Some(&3)); + assert_eq!(iter.try_for_each(Err), Err(3)); + assert_eq!(iter.peek(), Some(&4)); + assert_eq!(iter.try_for_each(Err), Err(4)); + assert_eq!(iter.peek(), None); + assert_eq!(iter.try_for_each(Err), Ok(())); + + let mut iter = (2..5).peekable(); + assert_eq!(iter.peek(), Some(&2)); + assert_eq!(iter.try_rfold((), |(), x| Err(x)), Err(4)); + assert_eq!(iter.peek(), Some(&2)); + assert_eq!(iter.try_rfold((), |(), x| Err(x)), Err(3)); + assert_eq!(iter.peek(), Some(&2)); + assert_eq!(iter.try_rfold((), |(), x| Err(x)), Err(2)); + assert_eq!(iter.peek(), None); + assert_eq!(iter.try_rfold((), |(), x| Err(x)), Ok(())); +} + +#[test] +fn test_peekable_non_fused() { + let mut iter = NonFused::new(empty::<i32>()).peekable(); + + assert_eq!(iter.peek(), None); + assert_eq!(iter.next_back(), None); +} diff --git a/library/core/tests/iter/adapters/scan.rs b/library/core/tests/iter/adapters/scan.rs new file mode 100644 index 000000000..1d28ca6b7 --- /dev/null +++ b/library/core/tests/iter/adapters/scan.rs @@ -0,0 +1,20 @@ +use core::iter::*; + +#[test] +fn test_iterator_scan() { + // test the type inference + fn add(old: &mut isize, new: &usize) -> Option<f64> { + *old += *new as isize; + Some(*old as f64) + } + let xs = [0, 1, 2, 3, 4]; + let ys = [0f64, 1.0, 3.0, 6.0, 10.0]; + + let it = xs.iter().scan(0, add); + let mut i = 0; + for x in it { + assert_eq!(x, ys[i]); + i += 1; + } + assert_eq!(i, ys.len()); +} diff --git a/library/core/tests/iter/adapters/skip.rs b/library/core/tests/iter/adapters/skip.rs new file mode 100644 index 000000000..65f235e86 --- /dev/null +++ b/library/core/tests/iter/adapters/skip.rs @@ -0,0 +1,203 @@ +use core::iter::*; + +use super::Unfuse; + +#[test] +fn test_iterator_skip() { + let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30]; + let ys = [13, 15, 16, 17, 19, 20, 30]; + let mut it = xs.iter().skip(5); + let mut i = 0; + while let Some(&x) = it.next() { + assert_eq!(x, ys[i]); + i += 1; + assert_eq!(it.len(), xs.len() - 5 - i); + } + assert_eq!(i, ys.len()); + assert_eq!(it.len(), 0); +} + +#[test] +fn test_iterator_skip_doubleended() { + let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30]; + let mut it = xs.iter().rev().skip(5); + assert_eq!(it.next(), Some(&15)); + assert_eq!(it.by_ref().rev().next(), Some(&0)); + assert_eq!(it.next(), Some(&13)); + assert_eq!(it.by_ref().rev().next(), Some(&1)); + assert_eq!(it.next(), Some(&5)); + assert_eq!(it.by_ref().rev().next(), Some(&2)); + assert_eq!(it.next(), Some(&3)); + assert_eq!(it.next(), None); + let mut it = xs.iter().rev().skip(5).rev(); + assert_eq!(it.next(), Some(&0)); + assert_eq!(it.rev().next(), Some(&15)); + let mut it_base = xs.iter(); + { + let mut it = it_base.by_ref().skip(5).rev(); + assert_eq!(it.next(), Some(&30)); + assert_eq!(it.next(), Some(&20)); + assert_eq!(it.next(), Some(&19)); + assert_eq!(it.next(), Some(&17)); + assert_eq!(it.next(), Some(&16)); + assert_eq!(it.next(), Some(&15)); + assert_eq!(it.next(), Some(&13)); + assert_eq!(it.next(), None); + } + // make sure the skipped parts have not been consumed + assert_eq!(it_base.next(), Some(&0)); + assert_eq!(it_base.next(), Some(&1)); + assert_eq!(it_base.next(), Some(&2)); + assert_eq!(it_base.next(), Some(&3)); + assert_eq!(it_base.next(), Some(&5)); + assert_eq!(it_base.next(), None); + let it = xs.iter().skip(5).rev(); + assert_eq!(it.last(), Some(&13)); +} + +#[test] +fn test_iterator_skip_nth() { + let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30]; + + let mut it = xs.iter().skip(0); + assert_eq!(it.nth(0), Some(&0)); + assert_eq!(it.nth(1), Some(&2)); + + let mut it = xs.iter().skip(5); + assert_eq!(it.nth(0), Some(&13)); + assert_eq!(it.nth(1), Some(&16)); + + let mut it = xs.iter().skip(12); + assert_eq!(it.nth(0), None); +} + +#[test] +fn test_skip_advance_by() { + assert_eq!((0..0).skip(10).advance_by(0), Ok(())); + assert_eq!((0..0).skip(10).advance_by(1), Err(0)); + assert_eq!((0u128..(usize::MAX as u128) + 1).skip(usize::MAX).advance_by(usize::MAX), Err(1)); + assert_eq!((0u128..u128::MAX).skip(usize::MAX).advance_by(1), Ok(())); + + assert_eq!((0..2).skip(1).advance_back_by(10), Err(1)); + assert_eq!((0..0).skip(1).advance_back_by(0), Ok(())); +} + +#[test] +fn test_iterator_skip_count() { + let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30]; + + assert_eq!(xs.iter().skip(0).count(), 12); + assert_eq!(xs.iter().skip(1).count(), 11); + assert_eq!(xs.iter().skip(11).count(), 1); + assert_eq!(xs.iter().skip(12).count(), 0); + assert_eq!(xs.iter().skip(13).count(), 0); +} + +#[test] +fn test_iterator_skip_last() { + let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30]; + + assert_eq!(xs.iter().skip(0).last(), Some(&30)); + assert_eq!(xs.iter().skip(1).last(), Some(&30)); + assert_eq!(xs.iter().skip(11).last(), Some(&30)); + assert_eq!(xs.iter().skip(12).last(), None); + assert_eq!(xs.iter().skip(13).last(), None); + + let mut it = xs.iter().skip(5); + assert_eq!(it.next(), Some(&13)); + assert_eq!(it.last(), Some(&30)); +} + +#[test] +fn test_iterator_skip_fold() { + let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30]; + let ys = [13, 15, 16, 17, 19, 20, 30]; + + let it = xs.iter().skip(5); + let i = it.fold(0, |i, &x| { + assert_eq!(x, ys[i]); + i + 1 + }); + assert_eq!(i, ys.len()); + + let mut it = xs.iter().skip(5); + assert_eq!(it.next(), Some(&ys[0])); // process skips before folding + let i = it.fold(1, |i, &x| { + assert_eq!(x, ys[i]); + i + 1 + }); + assert_eq!(i, ys.len()); + + let it = xs.iter().skip(5); + let i = it.rfold(ys.len(), |i, &x| { + let i = i - 1; + assert_eq!(x, ys[i]); + i + }); + assert_eq!(i, 0); + + let mut it = xs.iter().skip(5); + assert_eq!(it.next(), Some(&ys[0])); // process skips before folding + let i = it.rfold(ys.len(), |i, &x| { + let i = i - 1; + assert_eq!(x, ys[i]); + i + }); + assert_eq!(i, 1); +} + +#[test] +fn test_skip_try_folds() { + let f = &|acc, x| i32::checked_add(2 * acc, x); + assert_eq!((1..20).skip(9).try_fold(7, f), (10..20).try_fold(7, f)); + assert_eq!((1..20).skip(9).try_rfold(7, f), (10..20).try_rfold(7, f)); + + let mut iter = (0..30).skip(10); + assert_eq!(iter.try_fold(0, i8::checked_add), None); + assert_eq!(iter.next(), Some(20)); + assert_eq!(iter.try_rfold(0, i8::checked_add), None); + assert_eq!(iter.next_back(), Some(24)); +} + +#[test] +fn test_skip_nth_back() { + let xs = [0, 1, 2, 3, 4, 5]; + let mut it = xs.iter().skip(2); + assert_eq!(it.nth_back(0), Some(&5)); + assert_eq!(it.nth_back(1), Some(&3)); + assert_eq!(it.nth_back(0), Some(&2)); + assert_eq!(it.nth_back(0), None); + + let ys = [2, 3, 4, 5]; + let mut ity = ys.iter(); + let mut it = xs.iter().skip(2); + assert_eq!(it.nth_back(1), ity.nth_back(1)); + assert_eq!(it.clone().nth(0), ity.clone().nth(0)); + assert_eq!(it.nth_back(0), ity.nth_back(0)); + assert_eq!(it.clone().nth(0), ity.clone().nth(0)); + assert_eq!(it.nth_back(0), ity.nth_back(0)); + assert_eq!(it.clone().nth(0), ity.clone().nth(0)); + assert_eq!(it.nth_back(0), ity.nth_back(0)); + assert_eq!(it.clone().nth(0), ity.clone().nth(0)); + + let mut it = xs.iter().skip(2); + assert_eq!(it.nth_back(4), None); + assert_eq!(it.nth_back(0), None); + + let mut it = xs.iter(); + it.by_ref().skip(2).nth_back(3); + assert_eq!(it.next_back(), Some(&1)); + + let mut it = xs.iter(); + it.by_ref().skip(2).nth_back(10); + assert_eq!(it.next_back(), Some(&1)); +} + +#[test] +fn test_skip_non_fused() { + let non_fused = Unfuse::new(0..10); + + // `Skip` would previously exhaust the iterator in this `next` call and then erroneously try to + // advance it further. `Unfuse` tests that this doesn't happen by panicking in that scenario. + let _ = non_fused.skip(20).next(); +} diff --git a/library/core/tests/iter/adapters/skip_while.rs b/library/core/tests/iter/adapters/skip_while.rs new file mode 100644 index 000000000..929d4f6e6 --- /dev/null +++ b/library/core/tests/iter/adapters/skip_while.rs @@ -0,0 +1,50 @@ +use core::iter::*; + +#[test] +fn test_iterator_skip_while() { + let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19]; + let ys = [15, 16, 17, 19]; + let it = xs.iter().skip_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_iterator_skip_while_fold() { + let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19]; + let ys = [15, 16, 17, 19]; + let it = xs.iter().skip_while(|&x| *x < 15); + let i = it.fold(0, |i, &x| { + assert_eq!(x, ys[i]); + i + 1 + }); + assert_eq!(i, ys.len()); + + let mut it = xs.iter().skip_while(|&x| *x < 15); + assert_eq!(it.next(), Some(&ys[0])); // process skips before folding + let i = it.fold(1, |i, &x| { + assert_eq!(x, ys[i]); + i + 1 + }); + assert_eq!(i, ys.len()); +} + +#[test] +fn test_skip_while_try_fold() { + let f = &|acc, x| i32::checked_add(2 * acc, x); + fn p(&x: &i32) -> bool { + (x % 10) <= 5 + } + assert_eq!((1..20).skip_while(p).try_fold(7, f), (6..20).try_fold(7, f)); + let mut iter = (1..20).skip_while(p); + assert_eq!(iter.nth(5), Some(11)); + assert_eq!(iter.try_fold(7, f), (12..20).try_fold(7, f)); + + let mut iter = (0..50).skip_while(|&x| (x % 20) < 15); + assert_eq!(iter.try_fold(0, i8::checked_add), None); + assert_eq!(iter.next(), Some(23)); +} diff --git a/library/core/tests/iter/adapters/step_by.rs b/library/core/tests/iter/adapters/step_by.rs new file mode 100644 index 000000000..94f2fa8c2 --- /dev/null +++ b/library/core/tests/iter/adapters/step_by.rs @@ -0,0 +1,246 @@ +use core::iter::*; + +#[test] +fn test_iterator_step_by() { + // Identity + let mut it = (0..).step_by(1).take(3); + assert_eq!(it.next(), Some(0)); + assert_eq!(it.next(), Some(1)); + assert_eq!(it.next(), Some(2)); + assert_eq!(it.next(), None); + + let mut it = (0..).step_by(3).take(4); + assert_eq!(it.next(), Some(0)); + assert_eq!(it.next(), Some(3)); + assert_eq!(it.next(), Some(6)); + assert_eq!(it.next(), Some(9)); + assert_eq!(it.next(), None); + + let mut it = (0..3).step_by(1); + assert_eq!(it.next_back(), Some(2)); + assert_eq!(it.next_back(), Some(1)); + assert_eq!(it.next_back(), Some(0)); + assert_eq!(it.next_back(), None); + + let mut it = (0..11).step_by(3); + assert_eq!(it.next_back(), Some(9)); + assert_eq!(it.next_back(), Some(6)); + assert_eq!(it.next_back(), Some(3)); + assert_eq!(it.next_back(), Some(0)); + assert_eq!(it.next_back(), None); +} + +#[test] +fn test_iterator_step_by_nth() { + let mut it = (0..16).step_by(5); + assert_eq!(it.nth(0), Some(0)); + assert_eq!(it.nth(0), Some(5)); + assert_eq!(it.nth(0), Some(10)); + assert_eq!(it.nth(0), Some(15)); + assert_eq!(it.nth(0), None); + + let it = (0..18).step_by(5); + assert_eq!(it.clone().nth(0), Some(0)); + assert_eq!(it.clone().nth(1), Some(5)); + assert_eq!(it.clone().nth(2), Some(10)); + assert_eq!(it.clone().nth(3), Some(15)); + assert_eq!(it.clone().nth(4), None); + assert_eq!(it.clone().nth(42), None); +} + +#[test] +fn test_iterator_step_by_nth_overflow() { + #[cfg(target_pointer_width = "16")] + type Bigger = u32; + #[cfg(target_pointer_width = "32")] + type Bigger = u64; + #[cfg(target_pointer_width = "64")] + type Bigger = u128; + + #[derive(Clone)] + struct Test(Bigger); + impl Iterator for &mut Test { + type Item = i32; + fn next(&mut self) -> Option<Self::Item> { + Some(21) + } + fn nth(&mut self, n: usize) -> Option<Self::Item> { + self.0 += n as Bigger + 1; + Some(42) + } + } + + let mut it = Test(0); + let root = usize::MAX >> (usize::BITS / 2); + let n = root + 20; + (&mut it).step_by(n).nth(n); + assert_eq!(it.0, n as Bigger * n as Bigger); + + // large step + let mut it = Test(0); + (&mut it).step_by(usize::MAX).nth(5); + assert_eq!(it.0, (usize::MAX as Bigger) * 5); + + // n + 1 overflows + let mut it = Test(0); + (&mut it).step_by(2).nth(usize::MAX); + assert_eq!(it.0, (usize::MAX as Bigger) * 2); + + // n + 1 overflows + let mut it = Test(0); + (&mut it).step_by(1).nth(usize::MAX); + assert_eq!(it.0, (usize::MAX as Bigger) * 1); +} + +#[test] +fn test_iterator_step_by_nth_try_fold() { + let mut it = (0..).step_by(10); + assert_eq!(it.try_fold(0, i8::checked_add), None); + assert_eq!(it.next(), Some(60)); + assert_eq!(it.try_fold(0, i8::checked_add), None); + assert_eq!(it.next(), Some(90)); + + let mut it = (100..).step_by(10); + assert_eq!(it.try_fold(50, i8::checked_add), None); + assert_eq!(it.next(), Some(110)); + + let mut it = (100..=100).step_by(10); + assert_eq!(it.next(), Some(100)); + assert_eq!(it.try_fold(0, i8::checked_add), Some(0)); +} + +#[test] +fn test_iterator_step_by_nth_back() { + let mut it = (0..16).step_by(5); + assert_eq!(it.nth_back(0), Some(15)); + assert_eq!(it.nth_back(0), Some(10)); + assert_eq!(it.nth_back(0), Some(5)); + assert_eq!(it.nth_back(0), Some(0)); + assert_eq!(it.nth_back(0), None); + + let mut it = (0..16).step_by(5); + assert_eq!(it.next(), Some(0)); // to set `first_take` to `false` + assert_eq!(it.nth_back(0), Some(15)); + assert_eq!(it.nth_back(0), Some(10)); + assert_eq!(it.nth_back(0), Some(5)); + assert_eq!(it.nth_back(0), None); + + let it = || (0..18).step_by(5); + assert_eq!(it().nth_back(0), Some(15)); + assert_eq!(it().nth_back(1), Some(10)); + assert_eq!(it().nth_back(2), Some(5)); + assert_eq!(it().nth_back(3), Some(0)); + assert_eq!(it().nth_back(4), None); + assert_eq!(it().nth_back(42), None); +} + +#[test] +fn test_iterator_step_by_nth_try_rfold() { + let mut it = (0..100).step_by(10); + assert_eq!(it.try_rfold(0, i8::checked_add), None); + assert_eq!(it.next_back(), Some(70)); + assert_eq!(it.next(), Some(0)); + assert_eq!(it.try_rfold(0, i8::checked_add), None); + assert_eq!(it.next_back(), Some(30)); + + let mut it = (0..100).step_by(10); + assert_eq!(it.try_rfold(50, i8::checked_add), None); + assert_eq!(it.next_back(), Some(80)); + + let mut it = (100..=100).step_by(10); + assert_eq!(it.next_back(), Some(100)); + assert_eq!(it.try_fold(0, i8::checked_add), Some(0)); +} + +#[test] +#[should_panic] +fn test_iterator_step_by_zero() { + let mut it = (0..).step_by(0); + it.next(); +} + +#[test] +fn test_iterator_step_by_size_hint() { + struct StubSizeHint(usize, Option<usize>); + impl Iterator for StubSizeHint { + type Item = (); + fn next(&mut self) -> Option<()> { + self.0 -= 1; + if let Some(ref mut upper) = self.1 { + *upper -= 1; + } + Some(()) + } + fn size_hint(&self) -> (usize, Option<usize>) { + (self.0, self.1) + } + } + + // The two checks in each case are needed because the logic + // is different before the first call to `next()`. + + let mut it = StubSizeHint(10, Some(10)).step_by(1); + assert_eq!(it.size_hint(), (10, Some(10))); + it.next(); + assert_eq!(it.size_hint(), (9, Some(9))); + + // exact multiple + let mut it = StubSizeHint(10, Some(10)).step_by(3); + assert_eq!(it.size_hint(), (4, Some(4))); + it.next(); + assert_eq!(it.size_hint(), (3, Some(3))); + + // larger base range, but not enough to get another element + let mut it = StubSizeHint(12, Some(12)).step_by(3); + assert_eq!(it.size_hint(), (4, Some(4))); + it.next(); + assert_eq!(it.size_hint(), (3, Some(3))); + + // smaller base range, so fewer resulting elements + let mut it = StubSizeHint(9, Some(9)).step_by(3); + assert_eq!(it.size_hint(), (3, Some(3))); + it.next(); + assert_eq!(it.size_hint(), (2, Some(2))); + + // infinite upper bound + let mut it = StubSizeHint(usize::MAX, None).step_by(1); + assert_eq!(it.size_hint(), (usize::MAX, None)); + it.next(); + assert_eq!(it.size_hint(), (usize::MAX - 1, None)); + + // still infinite with larger step + let mut it = StubSizeHint(7, None).step_by(3); + assert_eq!(it.size_hint(), (3, None)); + it.next(); + assert_eq!(it.size_hint(), (2, None)); + + // propagates ExactSizeIterator + let a = [1, 2, 3, 4, 5]; + let it = a.iter().step_by(2); + assert_eq!(it.len(), 3); + + // Cannot be TrustedLen as a step greater than one makes an iterator + // with (usize::MAX, None) no longer meet the safety requirements + trait TrustedLenCheck { + fn test(self) -> bool; + } + impl<T: Iterator> TrustedLenCheck for T { + default fn test(self) -> bool { + false + } + } + impl<T: TrustedLen> TrustedLenCheck for T { + fn test(self) -> bool { + true + } + } + assert!(TrustedLenCheck::test(a.iter())); + assert!(!TrustedLenCheck::test(a.iter().step_by(1))); +} + +#[test] +fn test_step_by_skip() { + assert_eq!((0..640).step_by(128).skip(1).collect::<Vec<_>>(), [128, 256, 384, 512]); + assert_eq!((0..=50).step_by(10).nth(3), Some(30)); + assert_eq!((200..=255u8).step_by(10).nth(3), Some(230)); +} diff --git a/library/core/tests/iter/adapters/take.rs b/library/core/tests/iter/adapters/take.rs new file mode 100644 index 000000000..bfb659f0a --- /dev/null +++ b/library/core/tests/iter/adapters/take.rs @@ -0,0 +1,148 @@ +use core::iter::*; + +#[test] +fn test_iterator_take() { + let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19]; + let ys = [0, 1, 2, 3, 5]; + + let mut it = xs.iter().take(ys.len()); + let mut i = 0; + assert_eq!(it.len(), ys.len()); + while let Some(&x) = it.next() { + assert_eq!(x, ys[i]); + i += 1; + assert_eq!(it.len(), ys.len() - i); + } + assert_eq!(i, ys.len()); + assert_eq!(it.len(), 0); + + let mut it = xs.iter().take(ys.len()); + let mut i = 0; + assert_eq!(it.len(), ys.len()); + while let Some(&x) = it.next_back() { + i += 1; + assert_eq!(x, ys[ys.len() - i]); + assert_eq!(it.len(), ys.len() - i); + } + assert_eq!(i, ys.len()); + assert_eq!(it.len(), 0); +} + +#[test] +fn test_iterator_take_nth() { + let xs = [0, 1, 2, 4, 5]; + let mut it = xs.iter(); + { + let mut take = it.by_ref().take(3); + let mut i = 0; + while let Some(&x) = take.nth(0) { + assert_eq!(x, i); + i += 1; + } + } + assert_eq!(it.nth(1), Some(&5)); + assert_eq!(it.nth(0), None); + + let xs = [0, 1, 2, 3, 4]; + let mut it = xs.iter().take(7); + let mut i = 1; + while let Some(&x) = it.nth(1) { + assert_eq!(x, i); + i += 2; + } +} + +#[test] +fn test_iterator_take_nth_back() { + let xs = [0, 1, 2, 4, 5]; + let mut it = xs.iter(); + { + let mut take = it.by_ref().take(3); + let mut i = 0; + while let Some(&x) = take.nth_back(0) { + i += 1; + assert_eq!(x, 3 - i); + } + } + assert_eq!(it.nth_back(0), None); + + let xs = [0, 1, 2, 3, 4]; + let mut it = xs.iter().take(7); + assert_eq!(it.nth_back(1), Some(&3)); + assert_eq!(it.nth_back(1), Some(&1)); + assert_eq!(it.nth_back(1), None); +} + +#[test] +fn test_take_advance_by() { + let mut take = (0..10).take(3); + assert_eq!(take.advance_by(2), Ok(())); + assert_eq!(take.next(), Some(2)); + assert_eq!(take.advance_by(1), Err(0)); + + assert_eq!((0..0).take(10).advance_by(0), Ok(())); + assert_eq!((0..0).take(10).advance_by(1), Err(0)); + assert_eq!((0..10).take(4).advance_by(5), Err(4)); + + let mut take = (0..10).take(3); + assert_eq!(take.advance_back_by(2), Ok(())); + assert_eq!(take.next(), Some(0)); + assert_eq!(take.advance_back_by(1), Err(0)); + + assert_eq!((0..2).take(1).advance_back_by(10), Err(1)); + assert_eq!((0..0).take(1).advance_back_by(1), Err(0)); + assert_eq!((0..0).take(1).advance_back_by(0), Ok(())); + assert_eq!((0..usize::MAX).take(100).advance_back_by(usize::MAX), Err(100)); +} + +#[test] +fn test_iterator_take_short() { + let xs = [0, 1, 2, 3]; + + let mut it = xs.iter().take(5); + let mut i = 0; + assert_eq!(it.len(), xs.len()); + while let Some(&x) = it.next() { + assert_eq!(x, xs[i]); + i += 1; + assert_eq!(it.len(), xs.len() - i); + } + assert_eq!(i, xs.len()); + assert_eq!(it.len(), 0); + + let mut it = xs.iter().take(5); + let mut i = 0; + assert_eq!(it.len(), xs.len()); + while let Some(&x) = it.next_back() { + i += 1; + assert_eq!(x, xs[xs.len() - i]); + assert_eq!(it.len(), xs.len() - i); + } + assert_eq!(i, xs.len()); + assert_eq!(it.len(), 0); +} + +#[test] +fn test_take_try_folds() { + let f = &|acc, x| i32::checked_add(2 * acc, x); + assert_eq!((10..30).take(10).try_fold(7, f), (10..20).try_fold(7, f)); + assert_eq!((10..30).take(10).try_rfold(7, f), (10..20).try_rfold(7, f)); + + let mut iter = (10..30).take(20); + assert_eq!(iter.try_fold(0, i8::checked_add), None); + assert_eq!(iter.next(), Some(20)); + assert_eq!(iter.try_rfold(0, i8::checked_add), None); + assert_eq!(iter.next_back(), Some(24)); + + let mut iter = (2..20).take(3); + assert_eq!(iter.try_for_each(Err), Err(2)); + assert_eq!(iter.try_for_each(Err), Err(3)); + assert_eq!(iter.try_for_each(Err), Err(4)); + assert_eq!(iter.try_for_each(Err), Ok(())); + + let mut iter = (2..20).take(3).rev(); + assert_eq!(iter.try_for_each(Err), Err(4)); + assert_eq!(iter.try_for_each(Err), Err(3)); + assert_eq!(iter.try_for_each(Err), Err(2)); + assert_eq!(iter.try_for_each(Err), Ok(())); +} 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)); +} diff --git a/library/core/tests/iter/adapters/zip.rs b/library/core/tests/iter/adapters/zip.rs new file mode 100644 index 000000000..585cfbb90 --- /dev/null +++ b/library/core/tests/iter/adapters/zip.rs @@ -0,0 +1,315 @@ +use super::*; +use core::iter::*; + +#[test] +fn test_zip_nth() { + let xs = [0, 1, 2, 4, 5]; + let ys = [10, 11, 12]; + + let mut it = xs.iter().zip(&ys); + assert_eq!(it.nth(0), Some((&0, &10))); + assert_eq!(it.nth(1), Some((&2, &12))); + assert_eq!(it.nth(0), None); + + let mut it = xs.iter().zip(&ys); + assert_eq!(it.nth(3), None); + + let mut it = ys.iter().zip(&xs); + assert_eq!(it.nth(3), None); +} + +#[test] +fn test_zip_nth_side_effects() { + let mut a = Vec::new(); + let mut b = Vec::new(); + let value = [1, 2, 3, 4, 5, 6] + .iter() + .cloned() + .map(|n| { + a.push(n); + n * 10 + }) + .zip([2, 3, 4, 5, 6, 7, 8].iter().cloned().map(|n| { + b.push(n * 100); + n * 1000 + })) + .skip(1) + .nth(3); + assert_eq!(value, Some((50, 6000))); + assert_eq!(a, vec![1, 2, 3, 4, 5]); + assert_eq!(b, vec![200, 300, 400, 500, 600]); +} + +#[test] +fn test_zip_next_back_side_effects() { + let mut a = Vec::new(); + let mut b = Vec::new(); + let mut iter = [1, 2, 3, 4, 5, 6] + .iter() + .cloned() + .map(|n| { + a.push(n); + n * 10 + }) + .zip([2, 3, 4, 5, 6, 7, 8].iter().cloned().map(|n| { + b.push(n * 100); + n * 1000 + })); + + // The second iterator is one item longer, so `next_back` is called on it + // one more time. + assert_eq!(iter.next_back(), Some((60, 7000))); + assert_eq!(iter.next_back(), Some((50, 6000))); + assert_eq!(iter.next_back(), Some((40, 5000))); + assert_eq!(iter.next_back(), Some((30, 4000))); + assert_eq!(a, vec![6, 5, 4, 3]); + assert_eq!(b, vec![800, 700, 600, 500, 400]); +} + +#[test] +fn test_zip_nth_back_side_effects() { + let mut a = Vec::new(); + let mut b = Vec::new(); + let value = [1, 2, 3, 4, 5, 6] + .iter() + .cloned() + .map(|n| { + a.push(n); + n * 10 + }) + .zip([2, 3, 4, 5, 6, 7, 8].iter().cloned().map(|n| { + b.push(n * 100); + n * 1000 + })) + .nth_back(3); + assert_eq!(value, Some((30, 4000))); + assert_eq!(a, vec![6, 5, 4, 3]); + assert_eq!(b, vec![800, 700, 600, 500, 400]); +} + +#[test] +fn test_zip_next_back_side_effects_exhausted() { + let mut a = Vec::new(); + let mut b = Vec::new(); + let mut iter = [1, 2, 3, 4, 5, 6] + .iter() + .cloned() + .map(|n| { + a.push(n); + n * 10 + }) + .zip([2, 3, 4].iter().cloned().map(|n| { + b.push(n * 100); + n * 1000 + })); + + iter.next(); + iter.next(); + iter.next(); + iter.next(); + assert_eq!(iter.next_back(), None); + assert_eq!(a, vec![1, 2, 3, 4, 6, 5]); + assert_eq!(b, vec![200, 300, 400]); +} + +#[test] +fn test_zip_cloned_sideffectful() { + let xs = [CountClone::new(), CountClone::new(), CountClone::new(), CountClone::new()]; + let ys = [CountClone::new(), CountClone::new()]; + + for _ in xs.iter().cloned().zip(ys.iter().cloned()) {} + + assert_eq!(&xs, &[1, 1, 1, 0][..]); + assert_eq!(&ys, &[1, 1][..]); + + let xs = [CountClone::new(), CountClone::new()]; + let ys = [CountClone::new(), CountClone::new(), CountClone::new(), CountClone::new()]; + + for _ in xs.iter().cloned().zip(ys.iter().cloned()) {} + + assert_eq!(&xs, &[1, 1][..]); + assert_eq!(&ys, &[1, 1, 0, 0][..]); +} + +#[test] +fn test_zip_map_sideffectful() { + let mut xs = [0; 6]; + let mut ys = [0; 4]; + + for _ in xs.iter_mut().map(|x| *x += 1).zip(ys.iter_mut().map(|y| *y += 1)) {} + + assert_eq!(&xs, &[1, 1, 1, 1, 1, 0]); + assert_eq!(&ys, &[1, 1, 1, 1]); + + let mut xs = [0; 4]; + let mut ys = [0; 6]; + + for _ in xs.iter_mut().map(|x| *x += 1).zip(ys.iter_mut().map(|y| *y += 1)) {} + + assert_eq!(&xs, &[1, 1, 1, 1]); + assert_eq!(&ys, &[1, 1, 1, 1, 0, 0]); +} + +#[test] +fn test_zip_map_rev_sideffectful() { + let mut xs = [0; 6]; + let mut ys = [0; 4]; + + { + let mut it = xs.iter_mut().map(|x| *x += 1).zip(ys.iter_mut().map(|y| *y += 1)); + it.next_back(); + } + assert_eq!(&xs, &[0, 0, 0, 1, 1, 1]); + assert_eq!(&ys, &[0, 0, 0, 1]); + + let mut xs = [0; 6]; + let mut ys = [0; 4]; + + { + let mut it = xs.iter_mut().map(|x| *x += 1).zip(ys.iter_mut().map(|y| *y += 1)); + (&mut it).take(5).count(); + it.next_back(); + } + assert_eq!(&xs, &[1, 1, 1, 1, 1, 1]); + assert_eq!(&ys, &[1, 1, 1, 1]); +} + +#[test] +fn test_zip_nested_sideffectful() { + let mut xs = [0; 6]; + let ys = [0; 4]; + + { + // test that it has the side effect nested inside enumerate + let it = xs.iter_mut().map(|x| *x = 1).enumerate().zip(&ys); + it.count(); + } + assert_eq!(&xs, &[1, 1, 1, 1, 1, 0]); +} + +#[test] +fn test_zip_nth_back_side_effects_exhausted() { + let mut a = Vec::new(); + let mut b = Vec::new(); + let mut iter = [1, 2, 3, 4, 5, 6] + .iter() + .cloned() + .map(|n| { + a.push(n); + n * 10 + }) + .zip([2, 3, 4].iter().cloned().map(|n| { + b.push(n * 100); + n * 1000 + })); + + iter.next(); + iter.next(); + iter.next(); + iter.next(); + assert_eq!(iter.nth_back(0), None); + assert_eq!(a, vec![1, 2, 3, 4, 6, 5]); + assert_eq!(b, vec![200, 300, 400]); +} + +#[test] +fn test_zip_trusted_random_access_composition() { + let a = [0, 1, 2, 3, 4]; + let b = a; + let c = a; + + let a = a.iter().copied(); + let b = b.iter().copied(); + let mut c = c.iter().copied(); + c.next(); + + let mut z1 = a.zip(b); + assert_eq!(z1.next().unwrap(), (0, 0)); + + let mut z2 = z1.zip(c); + fn assert_trusted_random_access<T: TrustedRandomAccess>(_a: &T) {} + assert_trusted_random_access(&z2); + assert_eq!(z2.next().unwrap(), ((1, 1), 1)); +} + +#[test] +#[cfg(panic = "unwind")] +fn test_zip_trusted_random_access_next_back_drop() { + use std::panic::catch_unwind; + use std::panic::AssertUnwindSafe; + + let mut counter = 0; + + let it = [42].iter().map(|e| { + let c = counter; + counter += 1; + if c == 0 { + panic!("bomb"); + } + + e + }); + let it2 = [(); 0].iter(); + let mut zip = it.zip(it2); + catch_unwind(AssertUnwindSafe(|| { + zip.next_back(); + })) + .unwrap_err(); + assert!(zip.next().is_none()); + assert_eq!(counter, 1); +} + +#[test] +fn test_double_ended_zip() { + let xs = [1, 2, 3, 4, 5, 6]; + let ys = [1, 2, 3, 7]; + let mut it = xs.iter().cloned().zip(ys); + assert_eq!(it.next(), Some((1, 1))); + assert_eq!(it.next(), Some((2, 2))); + assert_eq!(it.next_back(), Some((4, 7))); + assert_eq!(it.next_back(), Some((3, 3))); + assert_eq!(it.next(), None); +} + +#[test] +fn test_issue_82282() { + fn overflowed_zip(arr: &[i32]) -> impl Iterator<Item = (i32, &())> { + static UNIT_EMPTY_ARR: [(); 0] = []; + + let mapped = arr.into_iter().map(|i| *i); + let mut zipped = mapped.zip(UNIT_EMPTY_ARR.iter()); + zipped.next(); + zipped + } + + let arr = [1, 2, 3]; + let zip = overflowed_zip(&arr).zip(overflowed_zip(&arr)); + + assert_eq!(zip.size_hint(), (0, Some(0))); + for _ in zip { + panic!(); + } +} + +#[test] +fn test_issue_82291() { + use std::cell::Cell; + + let mut v1 = [()]; + let v2 = [()]; + + let called = Cell::new(0); + + let mut zip = v1 + .iter_mut() + .map(|r| { + called.set(called.get() + 1); + r + }) + .zip(&v2); + + zip.next_back(); + assert_eq!(called.get(), 1); + zip.next(); + assert_eq!(called.get(), 1); +} |