| use core::cell::Cell; |
| use core::convert::TryFrom; |
| use core::iter::*; |
| use core::{i8, i16, isize}; |
| use core::usize; |
| |
| #[test] |
| fn test_lt() { |
| let empty: [isize; 0] = []; |
| let xs = [1,2,3]; |
| let ys = [1,2,0]; |
| |
| assert!(!xs.iter().lt(ys.iter())); |
| assert!(!xs.iter().le(ys.iter())); |
| assert!( xs.iter().gt(ys.iter())); |
| assert!( xs.iter().ge(ys.iter())); |
| |
| assert!( ys.iter().lt(xs.iter())); |
| assert!( ys.iter().le(xs.iter())); |
| assert!(!ys.iter().gt(xs.iter())); |
| assert!(!ys.iter().ge(xs.iter())); |
| |
| assert!( empty.iter().lt(xs.iter())); |
| assert!( empty.iter().le(xs.iter())); |
| assert!(!empty.iter().gt(xs.iter())); |
| assert!(!empty.iter().ge(xs.iter())); |
| |
| // Sequence with NaN |
| let u = [1.0f64, 2.0]; |
| let v = [0.0f64/0.0, 3.0]; |
| |
| assert!(!u.iter().lt(v.iter())); |
| assert!(!u.iter().le(v.iter())); |
| assert!(!u.iter().gt(v.iter())); |
| assert!(!u.iter().ge(v.iter())); |
| |
| let a = [0.0f64/0.0]; |
| let b = [1.0f64]; |
| let c = [2.0f64]; |
| |
| assert!(a.iter().lt(b.iter()) == (a[0] < b[0])); |
| assert!(a.iter().le(b.iter()) == (a[0] <= b[0])); |
| assert!(a.iter().gt(b.iter()) == (a[0] > b[0])); |
| assert!(a.iter().ge(b.iter()) == (a[0] >= b[0])); |
| |
| assert!(c.iter().lt(b.iter()) == (c[0] < b[0])); |
| assert!(c.iter().le(b.iter()) == (c[0] <= b[0])); |
| assert!(c.iter().gt(b.iter()) == (c[0] > b[0])); |
| assert!(c.iter().ge(b.iter()) == (c[0] >= b[0])); |
| } |
| |
| #[test] |
| fn test_multi_iter() { |
| let xs = [1,2,3,4]; |
| let ys = [4,3,2,1]; |
| assert!(xs.iter().eq(ys.iter().rev())); |
| assert!(xs.iter().lt(xs.iter().skip(2))); |
| } |
| |
| #[test] |
| fn test_cmp_by() { |
| use core::cmp::Ordering; |
| |
| let f = |x: i32, y: i32| (x * x).cmp(&y); |
| let xs = || [1, 2, 3, 4].iter().copied(); |
| let ys = || [1, 4, 16].iter().copied(); |
| |
| assert_eq!(xs().cmp_by(ys(), f), Ordering::Less); |
| assert_eq!(ys().cmp_by(xs(), f), Ordering::Greater); |
| assert_eq!(xs().cmp_by(xs().map(|x| x * x), f), Ordering::Equal); |
| assert_eq!(xs().rev().cmp_by(ys().rev(), f), Ordering::Greater); |
| assert_eq!(xs().cmp_by(ys().rev(), f), Ordering::Less); |
| assert_eq!(xs().cmp_by(ys().take(2), f), Ordering::Greater); |
| } |
| |
| #[test] |
| fn test_partial_cmp_by() { |
| use core::cmp::Ordering; |
| use core::f64; |
| |
| let f = |x: i32, y: i32| (x * x).partial_cmp(&y); |
| let xs = || [1, 2, 3, 4].iter().copied(); |
| let ys = || [1, 4, 16].iter().copied(); |
| |
| assert_eq!(xs().partial_cmp_by(ys(), f), Some(Ordering::Less)); |
| assert_eq!(ys().partial_cmp_by(xs(), f), Some(Ordering::Greater)); |
| assert_eq!(xs().partial_cmp_by(xs().map(|x| x * x), f), Some(Ordering::Equal)); |
| assert_eq!(xs().rev().partial_cmp_by(ys().rev(), f), Some(Ordering::Greater)); |
| assert_eq!(xs().partial_cmp_by(xs().rev(), f), Some(Ordering::Less)); |
| assert_eq!(xs().partial_cmp_by(ys().take(2), f), Some(Ordering::Greater)); |
| |
| let f = |x: f64, y: f64| (x * x).partial_cmp(&y); |
| let xs = || [1.0, 2.0, 3.0, 4.0].iter().copied(); |
| let ys = || [1.0, 4.0, f64::NAN, 16.0].iter().copied(); |
| |
| assert_eq!(xs().partial_cmp_by(ys(), f), None); |
| assert_eq!(ys().partial_cmp_by(xs(), f), Some(Ordering::Greater)); |
| } |
| |
| #[test] |
| fn test_eq_by() { |
| let f = |x: i32, y: i32| x * x == y; |
| let xs = || [1, 2, 3, 4].iter().copied(); |
| let ys = || [1, 4, 9, 16].iter().copied(); |
| |
| assert!(xs().eq_by(ys(), f)); |
| assert!(!ys().eq_by(xs(), f)); |
| assert!(!xs().eq_by(xs(), f)); |
| assert!(!ys().eq_by(ys(), f)); |
| |
| assert!(!xs().take(3).eq_by(ys(), f)); |
| assert!(!xs().eq_by(ys().take(3), f)); |
| assert!(xs().take(3).eq_by(ys().take(3), f)); |
| } |
| |
| #[test] |
| fn test_counter_from_iter() { |
| let it = (0..).step_by(5).take(10); |
| let xs: Vec<isize> = FromIterator::from_iter(it); |
| assert_eq!(xs, [0, 5, 10, 15, 20, 25, 30, 35, 40, 45]); |
| } |
| |
| #[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_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() { |
| struct Iter { |
| is_empty: bool, |
| } |
| |
| impl Iterator for Iter { |
| 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 Iter { |
| fn next_back(&mut self) -> Option<Self::Item> { |
| self.next() |
| } |
| } |
| |
| // 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 = Iter { is_empty: true }.chain(once(())); |
| assert_eq!(iter.next(), Some(())); |
| assert_eq!(iter.size_hint(), (0, Some(0))); |
| |
| let mut iter = once(()).chain(Iter { is_empty: true }); |
| assert_eq!(iter.next_back(), Some(())); |
| assert_eq!(iter.size_hint(), (0, Some(0))); |
| } |
| |
| #[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_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 = "8")] |
| type Bigger = u16; |
| #[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 >> (::std::mem::size_of::<usize>() * 8 / 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_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_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_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_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()); |
| } |
| |
| /// 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], |
| } |
| |
| pub fn cycle<T>(data: &[T]) -> CycleIter<'_, T> { |
| CycleIter { |
| 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 |
| } |
| } |
| |
| #[test] |
| fn test_iterator_peekable_remember_peek_none_1() { |
| // Check that the loop using .peek() terminates |
| let data = [1, 2, 3]; |
| let mut iter = cycle(&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 = cycle(&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 = cycle(&data).peekable(); |
| iter.peek(); |
| assert_eq!(iter.nth(0), Some(&0)); |
| |
| let mut iter = cycle(&data).peekable(); |
| iter.next(); |
| assert_eq!(iter.peek(), None); |
| assert_eq!(iter.nth(0), None); |
| } |
| |
| #[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_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_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_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_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_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_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()); |
| } |
| |
| #[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_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_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()); |
| } |
| |
| #[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); |
| } |
| |
| #[test] |
| fn test_iterator_nth() { |
| let v: &[_] = &[0, 1, 2, 3, 4]; |
| for i in 0..v.len() { |
| assert_eq!(v.iter().nth(i).unwrap(), &v[i]); |
| } |
| assert_eq!(v.iter().nth(v.len()), None); |
| } |
| |
| #[test] |
| fn test_iterator_nth_back() { |
| let v: &[_] = &[0, 1, 2, 3, 4]; |
| for i in 0..v.len() { |
| assert_eq!(v.iter().nth_back(i).unwrap(), &v[v.len() - 1 - i]); |
| } |
| assert_eq!(v.iter().nth_back(v.len()), None); |
| } |
| |
| #[test] |
| fn test_iterator_rev_nth_back() { |
| let v: &[_] = &[0, 1, 2, 3, 4]; |
| for i in 0..v.len() { |
| assert_eq!(v.iter().rev().nth_back(i).unwrap(), &v[i]); |
| } |
| assert_eq!(v.iter().rev().nth_back(v.len()), None); |
| } |
| |
| #[test] |
| fn test_iterator_rev_nth() { |
| let v: &[_] = &[0, 1, 2, 3, 4]; |
| for i in 0..v.len() { |
| assert_eq!(v.iter().rev().nth(i).unwrap(), &v[v.len() - 1 - i]); |
| } |
| assert_eq!(v.iter().rev().nth(v.len()), None); |
| } |
| |
| #[test] |
| fn test_iterator_last() { |
| let v: &[_] = &[0, 1, 2, 3, 4]; |
| assert_eq!(v.iter().last().unwrap(), &4); |
| assert_eq!(v[..1].iter().last().unwrap(), &0); |
| } |
| |
| #[test] |
| fn test_iterator_len() { |
| let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; |
| assert_eq!(v[..4].iter().count(), 4); |
| assert_eq!(v[..10].iter().count(), 10); |
| assert_eq!(v[..0].iter().count(), 0); |
| } |
| |
| #[test] |
| fn test_iterator_sum() { |
| let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; |
| assert_eq!(v[..4].iter().cloned().sum::<i32>(), 6); |
| assert_eq!(v.iter().cloned().sum::<i32>(), 55); |
| assert_eq!(v[..0].iter().cloned().sum::<i32>(), 0); |
| } |
| |
| #[test] |
| fn test_iterator_sum_result() { |
| let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)]; |
| assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Ok(10)); |
| let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)]; |
| assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Err(())); |
| |
| #[derive(PartialEq, Debug)] |
| struct S(Result<i32, ()>); |
| |
| impl Sum<Result<i32, ()>> for S { |
| fn sum<I: Iterator<Item = Result<i32, ()>>>(mut iter: I) -> Self { |
| // takes the sum by repeatedly calling `next` on `iter`, |
| // thus testing that repeated calls to `ResultShunt::try_fold` |
| // produce the expected results |
| Self(iter.by_ref().sum()) |
| } |
| } |
| |
| let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)]; |
| assert_eq!(v.iter().cloned().sum::<S>(), S(Ok(10))); |
| let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)]; |
| assert_eq!(v.iter().cloned().sum::<S>(), S(Err(()))); |
| } |
| |
| #[test] |
| fn test_iterator_sum_option() { |
| let v: &[Option<i32>] = &[Some(1), Some(2), Some(3), Some(4)]; |
| assert_eq!(v.iter().cloned().sum::<Option<i32>>(), Some(10)); |
| let v: &[Option<i32>] = &[Some(1), None, Some(3), Some(4)]; |
| assert_eq!(v.iter().cloned().sum::<Option<i32>>(), None); |
| } |
| |
| #[test] |
| fn test_iterator_product() { |
| let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; |
| assert_eq!(v[..4].iter().cloned().product::<i32>(), 0); |
| assert_eq!(v[1..5].iter().cloned().product::<i32>(), 24); |
| assert_eq!(v[..0].iter().cloned().product::<i32>(), 1); |
| } |
| |
| #[test] |
| fn test_iterator_product_result() { |
| let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)]; |
| assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Ok(24)); |
| let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)]; |
| assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Err(())); |
| } |
| |
| /// A wrapper struct that implements `Eq` and `Ord` based on the wrapped |
| /// integer modulo 3. Used to test that `Iterator::max` and `Iterator::min` |
| /// return the correct element if some of them are equal. |
| #[derive(Debug)] |
| struct Mod3(i32); |
| |
| impl PartialEq for Mod3 { |
| fn eq(&self, other: &Self) -> bool { |
| self.0 % 3 == other.0 % 3 |
| } |
| } |
| |
| impl Eq for Mod3 {} |
| |
| impl PartialOrd for Mod3 { |
| fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> { |
| Some(self.cmp(other)) |
| } |
| } |
| |
| impl Ord for Mod3 { |
| fn cmp(&self, other: &Self) -> core::cmp::Ordering { |
| (self.0 % 3).cmp(&(other.0 % 3)) |
| } |
| } |
| |
| #[test] |
| fn test_iterator_product_option() { |
| let v: &[Option<i32>] = &[Some(1), Some(2), Some(3), Some(4)]; |
| assert_eq!(v.iter().cloned().product::<Option<i32>>(), Some(24)); |
| let v: &[Option<i32>] = &[Some(1), None, Some(3), Some(4)]; |
| assert_eq!(v.iter().cloned().product::<Option<i32>>(), None); |
| } |
| |
| #[test] |
| fn test_iterator_max() { |
| let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; |
| assert_eq!(v[..4].iter().cloned().max(), Some(3)); |
| assert_eq!(v.iter().cloned().max(), Some(10)); |
| assert_eq!(v[..0].iter().cloned().max(), None); |
| assert_eq!(v.iter().cloned().map(Mod3).max().map(|x| x.0), Some(8)); |
| } |
| |
| #[test] |
| fn test_iterator_min() { |
| let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; |
| assert_eq!(v[..4].iter().cloned().min(), Some(0)); |
| assert_eq!(v.iter().cloned().min(), Some(0)); |
| assert_eq!(v[..0].iter().cloned().min(), None); |
| assert_eq!(v.iter().cloned().map(Mod3).min().map(|x| x.0), Some(0)); |
| } |
| |
| #[test] |
| fn test_iterator_size_hint() { |
| let c = (0..).step_by(1); |
| let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]; |
| let v2 = &[10, 11, 12]; |
| let vi = v.iter(); |
| |
| assert_eq!((0..).size_hint(), (usize::MAX, None)); |
| assert_eq!(c.size_hint(), (usize::MAX, None)); |
| assert_eq!(vi.clone().size_hint(), (10, Some(10))); |
| |
| assert_eq!(c.clone().take(5).size_hint(), (5, Some(5))); |
| assert_eq!(c.clone().skip(5).size_hint().1, None); |
| assert_eq!(c.clone().take_while(|_| false).size_hint(), (0, None)); |
| assert_eq!(c.clone().skip_while(|_| false).size_hint(), (0, None)); |
| assert_eq!(c.clone().enumerate().size_hint(), (usize::MAX, None)); |
| assert_eq!(c.clone().chain(vi.clone().cloned()).size_hint(), (usize::MAX, None)); |
| assert_eq!(c.clone().zip(vi.clone()).size_hint(), (10, Some(10))); |
| assert_eq!(c.clone().scan(0, |_,_| Some(0)).size_hint(), (0, None)); |
| assert_eq!(c.clone().filter(|_| false).size_hint(), (0, None)); |
| assert_eq!(c.clone().map(|_| 0).size_hint(), (usize::MAX, None)); |
| assert_eq!(c.filter_map(|_| Some(0)).size_hint(), (0, None)); |
| |
| assert_eq!(vi.clone().take(5).size_hint(), (5, Some(5))); |
| assert_eq!(vi.clone().take(12).size_hint(), (10, Some(10))); |
| assert_eq!(vi.clone().skip(3).size_hint(), (7, Some(7))); |
| assert_eq!(vi.clone().skip(12).size_hint(), (0, Some(0))); |
| assert_eq!(vi.clone().take_while(|_| false).size_hint(), (0, Some(10))); |
| assert_eq!(vi.clone().skip_while(|_| false).size_hint(), (0, Some(10))); |
| assert_eq!(vi.clone().enumerate().size_hint(), (10, Some(10))); |
| assert_eq!(vi.clone().chain(v2).size_hint(), (13, Some(13))); |
| assert_eq!(vi.clone().zip(v2).size_hint(), (3, Some(3))); |
| assert_eq!(vi.clone().scan(0, |_,_| Some(0)).size_hint(), (0, Some(10))); |
| assert_eq!(vi.clone().filter(|_| false).size_hint(), (0, Some(10))); |
| assert_eq!(vi.clone().map(|&i| i+1).size_hint(), (10, Some(10))); |
| assert_eq!(vi.filter_map(|_| Some(0)).size_hint(), (0, Some(10))); |
| } |
| |
| #[test] |
| fn test_collect() { |
| let a = vec![1, 2, 3, 4, 5]; |
| let b: Vec<isize> = a.iter().cloned().collect(); |
| assert!(a == b); |
| } |
| |
| #[test] |
| fn test_all() { |
| let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]); |
| assert!(v.iter().all(|&x| x < 10)); |
| assert!(!v.iter().all(|&x| x % 2 == 0)); |
| assert!(!v.iter().all(|&x| x > 100)); |
| assert!(v[..0].iter().all(|_| panic!())); |
| } |
| |
| #[test] |
| fn test_any() { |
| let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]); |
| assert!(v.iter().any(|&x| x < 10)); |
| assert!(v.iter().any(|&x| x % 2 == 0)); |
| assert!(!v.iter().any(|&x| x > 100)); |
| assert!(!v[..0].iter().any(|_| panic!())); |
| } |
| |
| #[test] |
| fn test_find() { |
| let v: &[isize] = &[1, 3, 9, 27, 103, 14, 11]; |
| assert_eq!(*v.iter().find(|&&x| x & 1 == 0).unwrap(), 14); |
| assert_eq!(*v.iter().find(|&&x| x % 3 == 0).unwrap(), 3); |
| assert!(v.iter().find(|&&x| x % 12 == 0).is_none()); |
| } |
| |
| #[test] |
| fn test_find_map() { |
| let xs: &[isize] = &[]; |
| assert_eq!(xs.iter().find_map(half_if_even), None); |
| let xs: &[isize] = &[3, 5]; |
| assert_eq!(xs.iter().find_map(half_if_even), None); |
| let xs: &[isize] = &[4, 5]; |
| assert_eq!(xs.iter().find_map(half_if_even), Some(2)); |
| let xs: &[isize] = &[3, 6]; |
| assert_eq!(xs.iter().find_map(half_if_even), Some(3)); |
| |
| let xs: &[isize] = &[1, 2, 3, 4, 5, 6, 7]; |
| let mut iter = xs.iter(); |
| assert_eq!(iter.find_map(half_if_even), Some(1)); |
| assert_eq!(iter.find_map(half_if_even), Some(2)); |
| assert_eq!(iter.find_map(half_if_even), Some(3)); |
| assert_eq!(iter.next(), Some(&7)); |
| |
| fn half_if_even(x: &isize) -> Option<isize> { |
| if x % 2 == 0 { |
| Some(x / 2) |
| } else { |
| None |
| } |
| } |
| } |
| |
| #[test] |
| fn test_position() { |
| let v = &[1, 3, 9, 27, 103, 14, 11]; |
| assert_eq!(v.iter().position(|x| *x & 1 == 0).unwrap(), 5); |
| assert_eq!(v.iter().position(|x| *x % 3 == 0).unwrap(), 1); |
| assert!(v.iter().position(|x| *x % 12 == 0).is_none()); |
| } |
| |
| #[test] |
| fn test_count() { |
| let xs = &[1, 2, 2, 1, 5, 9, 0, 2]; |
| assert_eq!(xs.iter().filter(|x| **x == 2).count(), 3); |
| assert_eq!(xs.iter().filter(|x| **x == 5).count(), 1); |
| assert_eq!(xs.iter().filter(|x| **x == 95).count(), 0); |
| } |
| |
| #[test] |
| fn test_max_by_key() { |
| let xs: &[isize] = &[-3, 0, 1, 5, -10]; |
| assert_eq!(*xs.iter().max_by_key(|x| x.abs()).unwrap(), -10); |
| } |
| |
| #[test] |
| fn test_max_by() { |
| let xs: &[isize] = &[-3, 0, 1, 5, -10]; |
| assert_eq!(*xs.iter().max_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), -10); |
| } |
| |
| #[test] |
| fn test_min_by_key() { |
| let xs: &[isize] = &[-3, 0, 1, 5, -10]; |
| assert_eq!(*xs.iter().min_by_key(|x| x.abs()).unwrap(), 0); |
| } |
| |
| #[test] |
| fn test_min_by() { |
| let xs: &[isize] = &[-3, 0, 1, 5, -10]; |
| assert_eq!(*xs.iter().min_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), 0); |
| } |
| |
| #[test] |
| fn test_by_ref() { |
| let mut xs = 0..10; |
| // sum the first five values |
| let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b); |
| assert_eq!(partial_sum, 10); |
| assert_eq!(xs.next(), Some(5)); |
| } |
| |
| #[test] |
| fn test_rev() { |
| let xs = [2, 4, 6, 8, 10, 12, 14, 16]; |
| let mut it = xs.iter(); |
| it.next(); |
| it.next(); |
| assert!(it.rev().cloned().collect::<Vec<isize>>() == |
| vec![16, 14, 12, 10, 8, 6]); |
| } |
| |
| #[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); |
| } |
| |
| #[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_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); |
| } |
| |
| #[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); |
| } |
| |
| #[test] |
| fn test_double_ended_zip() { |
| let xs = [1, 2, 3, 4, 5, 6]; |
| let ys = [1, 2, 3, 7]; |
| let a = xs.iter().cloned(); |
| let b = ys.iter().cloned(); |
| let mut it = a.zip(b); |
| 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_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); |
| } |
| |
| #[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); |
| } |
| |
| #[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)); |
| } |
| |
| #[test] |
| fn test_rposition() { |
| fn f(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'b' } |
| fn g(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'd' } |
| let v = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')]; |
| |
| assert_eq!(v.iter().rposition(f), Some(3)); |
| assert!(v.iter().rposition(g).is_none()); |
| } |
| |
| #[test] |
| fn test_rev_rposition() { |
| let v = [0, 0, 1, 1]; |
| assert_eq!(v.iter().rev().rposition(|&x| x == 1), Some(1)); |
| } |
| |
| #[test] |
| #[should_panic] |
| fn test_rposition_panic() { |
| let v: [(Box<_>, Box<_>); 4] = |
| [(box 0, box 0), (box 0, box 0), |
| (box 0, box 0), (box 0, box 0)]; |
| let mut i = 0; |
| v.iter().rposition(|_elt| { |
| if i == 2 { |
| panic!() |
| } |
| i += 1; |
| false |
| }); |
| } |
| |
| |
| #[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); |
| } |
| |
| #[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_double_ended_range() { |
| assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]); |
| for _ in (10..0).rev() { |
| panic!("unreachable"); |
| } |
| |
| assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]); |
| for _ in (10..0).rev() { |
| panic!("unreachable"); |
| } |
| } |
| |
| #[test] |
| fn test_range() { |
| assert_eq!((0..5).collect::<Vec<_>>(), [0, 1, 2, 3, 4]); |
| assert_eq!((-10..-1).collect::<Vec<_>>(), [-10, -9, -8, -7, -6, -5, -4, -3, -2]); |
| assert_eq!((0..5).rev().collect::<Vec<_>>(), [4, 3, 2, 1, 0]); |
| assert_eq!((200..-5).count(), 0); |
| assert_eq!((200..-5).rev().count(), 0); |
| assert_eq!((200..200).count(), 0); |
| assert_eq!((200..200).rev().count(), 0); |
| |
| assert_eq!((0..100).size_hint(), (100, Some(100))); |
| // this test is only meaningful when sizeof usize < sizeof u64 |
| assert_eq!((usize::MAX - 1..usize::MAX).size_hint(), (1, Some(1))); |
| assert_eq!((-10..-1).size_hint(), (9, Some(9))); |
| assert_eq!((-1..-10).size_hint(), (0, Some(0))); |
| |
| assert_eq!((-70..58).size_hint(), (128, Some(128))); |
| assert_eq!((-128..127).size_hint(), (255, Some(255))); |
| assert_eq!((-2..isize::MAX).size_hint(), |
| (isize::MAX as usize + 2, Some(isize::MAX as usize + 2))); |
| } |
| |
| #[test] |
| fn test_range_exhaustion() { |
| let mut r = 10..10; |
| assert!(r.is_empty()); |
| assert_eq!(r.next(), None); |
| assert_eq!(r.next_back(), None); |
| assert_eq!(r, 10..10); |
| |
| let mut r = 10..12; |
| assert_eq!(r.next(), Some(10)); |
| assert_eq!(r.next(), Some(11)); |
| assert!(r.is_empty()); |
| assert_eq!(r, 12..12); |
| assert_eq!(r.next(), None); |
| |
| let mut r = 10..12; |
| assert_eq!(r.next_back(), Some(11)); |
| assert_eq!(r.next_back(), Some(10)); |
| assert!(r.is_empty()); |
| assert_eq!(r, 10..10); |
| assert_eq!(r.next_back(), None); |
| |
| let mut r = 100..10; |
| assert!(r.is_empty()); |
| assert_eq!(r.next(), None); |
| assert_eq!(r.next_back(), None); |
| assert_eq!(r, 100..10); |
| } |
| |
| #[test] |
| fn test_range_inclusive_exhaustion() { |
| let mut r = 10..=10; |
| assert_eq!(r.next(), Some(10)); |
| assert!(r.is_empty()); |
| assert_eq!(r.next(), None); |
| assert_eq!(r.next(), None); |
| |
| let mut r = 10..=10; |
| assert_eq!(r.next_back(), Some(10)); |
| assert!(r.is_empty()); |
| assert_eq!(r.next_back(), None); |
| |
| let mut r = 10..=12; |
| assert_eq!(r.next(), Some(10)); |
| assert_eq!(r.next(), Some(11)); |
| assert_eq!(r.next(), Some(12)); |
| assert!(r.is_empty()); |
| assert_eq!(r.next(), None); |
| |
| let mut r = 10..=12; |
| assert_eq!(r.next_back(), Some(12)); |
| assert_eq!(r.next_back(), Some(11)); |
| assert_eq!(r.next_back(), Some(10)); |
| assert!(r.is_empty()); |
| assert_eq!(r.next_back(), None); |
| |
| let mut r = 10..=12; |
| assert_eq!(r.nth(2), Some(12)); |
| assert!(r.is_empty()); |
| assert_eq!(r.next(), None); |
| |
| let mut r = 10..=12; |
| assert_eq!(r.nth(5), None); |
| assert!(r.is_empty()); |
| assert_eq!(r.next(), None); |
| |
| let mut r = 100..=10; |
| assert_eq!(r.next(), None); |
| assert!(r.is_empty()); |
| assert_eq!(r.next(), None); |
| assert_eq!(r.next(), None); |
| assert_eq!(r, 100..=10); |
| |
| let mut r = 100..=10; |
| assert_eq!(r.next_back(), None); |
| assert!(r.is_empty()); |
| assert_eq!(r.next_back(), None); |
| assert_eq!(r.next_back(), None); |
| assert_eq!(r, 100..=10); |
| } |
| |
| #[test] |
| fn test_range_nth() { |
| assert_eq!((10..15).nth(0), Some(10)); |
| assert_eq!((10..15).nth(1), Some(11)); |
| assert_eq!((10..15).nth(4), Some(14)); |
| assert_eq!((10..15).nth(5), None); |
| |
| let mut r = 10..20; |
| assert_eq!(r.nth(2), Some(12)); |
| assert_eq!(r, 13..20); |
| assert_eq!(r.nth(2), Some(15)); |
| assert_eq!(r, 16..20); |
| assert_eq!(r.nth(10), None); |
| assert_eq!(r, 20..20); |
| } |
| |
| #[test] |
| fn test_range_nth_back() { |
| assert_eq!((10..15).nth_back(0), Some(14)); |
| assert_eq!((10..15).nth_back(1), Some(13)); |
| assert_eq!((10..15).nth_back(4), Some(10)); |
| assert_eq!((10..15).nth_back(5), None); |
| assert_eq!((-120..80_i8).nth_back(199), Some(-120)); |
| |
| let mut r = 10..20; |
| assert_eq!(r.nth_back(2), Some(17)); |
| assert_eq!(r, 10..17); |
| assert_eq!(r.nth_back(2), Some(14)); |
| assert_eq!(r, 10..14); |
| assert_eq!(r.nth_back(10), None); |
| assert_eq!(r, 10..10); |
| } |
| |
| #[test] |
| fn test_range_from_nth() { |
| assert_eq!((10..).nth(0), Some(10)); |
| assert_eq!((10..).nth(1), Some(11)); |
| assert_eq!((10..).nth(4), Some(14)); |
| |
| let mut r = 10..; |
| assert_eq!(r.nth(2), Some(12)); |
| assert_eq!(r, 13..); |
| assert_eq!(r.nth(2), Some(15)); |
| assert_eq!(r, 16..); |
| assert_eq!(r.nth(10), Some(26)); |
| assert_eq!(r, 27..); |
| |
| assert_eq!((0..).size_hint(), (usize::MAX, None)); |
| } |
| |
| fn is_trusted_len<I: TrustedLen>(_: I) {} |
| |
| #[test] |
| fn test_range_from_take() { |
| let mut it = (0..).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); |
| is_trusted_len((0..).take(3)); |
| assert_eq!((0..).take(3).size_hint(), (3, Some(3))); |
| assert_eq!((0..).take(0).size_hint(), (0, Some(0))); |
| assert_eq!((0..).take(usize::MAX).size_hint(), (usize::MAX, Some(usize::MAX))); |
| } |
| |
| #[test] |
| fn test_range_from_take_collect() { |
| let v: Vec<_> = (0..).take(3).collect(); |
| assert_eq!(v, vec![0, 1, 2]); |
| } |
| |
| #[test] |
| fn test_range_inclusive_nth() { |
| assert_eq!((10..=15).nth(0), Some(10)); |
| assert_eq!((10..=15).nth(1), Some(11)); |
| assert_eq!((10..=15).nth(5), Some(15)); |
| assert_eq!((10..=15).nth(6), None); |
| |
| let mut r = 10_u8..=20; |
| assert_eq!(r.nth(2), Some(12)); |
| assert_eq!(r, 13..=20); |
| assert_eq!(r.nth(2), Some(15)); |
| assert_eq!(r, 16..=20); |
| assert_eq!(r.is_empty(), false); |
| assert_eq!(ExactSizeIterator::is_empty(&r), false); |
| assert_eq!(r.nth(10), None); |
| assert_eq!(r.is_empty(), true); |
| assert_eq!(ExactSizeIterator::is_empty(&r), true); |
| } |
| |
| #[test] |
| fn test_range_inclusive_nth_back() { |
| assert_eq!((10..=15).nth_back(0), Some(15)); |
| assert_eq!((10..=15).nth_back(1), Some(14)); |
| assert_eq!((10..=15).nth_back(5), Some(10)); |
| assert_eq!((10..=15).nth_back(6), None); |
| assert_eq!((-120..=80_i8).nth_back(200), Some(-120)); |
| |
| let mut r = 10_u8..=20; |
| assert_eq!(r.nth_back(2), Some(18)); |
| assert_eq!(r, 10..=17); |
| assert_eq!(r.nth_back(2), Some(15)); |
| assert_eq!(r, 10..=14); |
| assert_eq!(r.is_empty(), false); |
| assert_eq!(ExactSizeIterator::is_empty(&r), false); |
| assert_eq!(r.nth_back(10), None); |
| assert_eq!(r.is_empty(), true); |
| assert_eq!(ExactSizeIterator::is_empty(&r), true); |
| } |
| |
| #[test] |
| fn test_range_step() { |
| #![allow(deprecated)] |
| |
| assert_eq!((0..20).step_by(5).collect::<Vec<isize>>(), [0, 5, 10, 15]); |
| assert_eq!((1..21).rev().step_by(5).collect::<Vec<isize>>(), [20, 15, 10, 5]); |
| assert_eq!((1..21).rev().step_by(6).collect::<Vec<isize>>(), [20, 14, 8, 2]); |
| assert_eq!((200..255).step_by(50).collect::<Vec<u8>>(), [200, 250]); |
| assert_eq!((200..-5).step_by(1).collect::<Vec<isize>>(), []); |
| assert_eq!((200..200).step_by(1).collect::<Vec<isize>>(), []); |
| |
| assert_eq!((0..20).step_by(1).size_hint(), (20, Some(20))); |
| assert_eq!((0..20).step_by(21).size_hint(), (1, Some(1))); |
| assert_eq!((0..20).step_by(5).size_hint(), (4, Some(4))); |
| assert_eq!((1..21).rev().step_by(5).size_hint(), (4, Some(4))); |
| assert_eq!((1..21).rev().step_by(6).size_hint(), (4, Some(4))); |
| assert_eq!((20..-5).step_by(1).size_hint(), (0, Some(0))); |
| assert_eq!((20..20).step_by(1).size_hint(), (0, Some(0))); |
| assert_eq!((i8::MIN..i8::MAX).step_by(-(i8::MIN as i32) as usize).size_hint(), (2, Some(2))); |
| assert_eq!((i16::MIN..i16::MAX).step_by(i16::MAX as usize).size_hint(), (3, Some(3))); |
| assert_eq!((isize::MIN..isize::MAX).step_by(1).size_hint(), (usize::MAX, Some(usize::MAX))); |
| } |
| |
| #[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)); |
| } |
| |
| #[test] |
| fn test_range_inclusive_step() { |
| assert_eq!((0..=50).step_by(10).collect::<Vec<_>>(), [0, 10, 20, 30, 40, 50]); |
| assert_eq!((0..=5).step_by(1).collect::<Vec<_>>(), [0, 1, 2, 3, 4, 5]); |
| assert_eq!((200..=255u8).step_by(10).collect::<Vec<_>>(), [200, 210, 220, 230, 240, 250]); |
| assert_eq!((250..=255u8).step_by(1).collect::<Vec<_>>(), [250, 251, 252, 253, 254, 255]); |
| } |
| |
| #[test] |
| fn test_range_last_max() { |
| assert_eq!((0..20).last(), Some(19)); |
| assert_eq!((-20..0).last(), Some(-1)); |
| assert_eq!((5..5).last(), None); |
| |
| assert_eq!((0..20).max(), Some(19)); |
| assert_eq!((-20..0).max(), Some(-1)); |
| assert_eq!((5..5).max(), None); |
| } |
| |
| #[test] |
| fn test_range_inclusive_last_max() { |
| assert_eq!((0..=20).last(), Some(20)); |
| assert_eq!((-20..=0).last(), Some(0)); |
| assert_eq!((5..=5).last(), Some(5)); |
| let mut r = 10..=10; |
| r.next(); |
| assert_eq!(r.last(), None); |
| |
| assert_eq!((0..=20).max(), Some(20)); |
| assert_eq!((-20..=0).max(), Some(0)); |
| assert_eq!((5..=5).max(), Some(5)); |
| let mut r = 10..=10; |
| r.next(); |
| assert_eq!(r.max(), None); |
| } |
| |
| #[test] |
| fn test_range_min() { |
| assert_eq!((0..20).min(), Some(0)); |
| assert_eq!((-20..0).min(), Some(-20)); |
| assert_eq!((5..5).min(), None); |
| } |
| |
| #[test] |
| fn test_range_inclusive_min() { |
| assert_eq!((0..=20).min(), Some(0)); |
| assert_eq!((-20..=0).min(), Some(-20)); |
| assert_eq!((5..=5).min(), Some(5)); |
| let mut r = 10..=10; |
| r.next(); |
| assert_eq!(r.min(), None); |
| } |
| |
| #[test] |
| fn test_range_inclusive_folds() { |
| assert_eq!((1..=10).sum::<i32>(), 55); |
| assert_eq!((1..=10).rev().sum::<i32>(), 55); |
| |
| let mut it = 44..=50; |
| assert_eq!(it.try_fold(0, i8::checked_add), None); |
| assert_eq!(it, 47..=50); |
| assert_eq!(it.try_fold(0, i8::checked_add), None); |
| assert_eq!(it, 50..=50); |
| assert_eq!(it.try_fold(0, i8::checked_add), Some(50)); |
| assert!(it.is_empty()); |
| assert_eq!(it.try_fold(0, i8::checked_add), Some(0)); |
| assert!(it.is_empty()); |
| |
| let mut it = 40..=47; |
| assert_eq!(it.try_rfold(0, i8::checked_add), None); |
| assert_eq!(it, 40..=44); |
| assert_eq!(it.try_rfold(0, i8::checked_add), None); |
| assert_eq!(it, 40..=41); |
| assert_eq!(it.try_rfold(0, i8::checked_add), Some(81)); |
| assert!(it.is_empty()); |
| assert_eq!(it.try_rfold(0, i8::checked_add), Some(0)); |
| assert!(it.is_empty()); |
| |
| let mut it = 10..=20; |
| assert_eq!(it.try_fold(0, |a,b| Some(a+b)), Some(165)); |
| assert!(it.is_empty()); |
| assert_eq!(it.try_fold(0, |a,b| Some(a+b)), Some(0)); |
| assert!(it.is_empty()); |
| |
| let mut it = 10..=20; |
| assert_eq!(it.try_rfold(0, |a,b| Some(a+b)), Some(165)); |
| assert!(it.is_empty()); |
| assert_eq!(it.try_rfold(0, |a,b| Some(a+b)), Some(0)); |
| assert!(it.is_empty()); |
| } |
| |
| #[test] |
| fn test_range_size_hint() { |
| use core::usize::MAX as UMAX; |
| assert_eq!((0..0usize).size_hint(), (0, Some(0))); |
| assert_eq!((0..100usize).size_hint(), (100, Some(100))); |
| assert_eq!((0..UMAX).size_hint(), (UMAX, Some(UMAX))); |
| |
| let umax = u128::try_from(UMAX).unwrap(); |
| assert_eq!((0..0u128).size_hint(), (0, Some(0))); |
| assert_eq!((0..100u128).size_hint(), (100, Some(100))); |
| assert_eq!((0..umax).size_hint(), (UMAX, Some(UMAX))); |
| assert_eq!((0..umax + 1).size_hint(), (UMAX, None)); |
| |
| use core::isize::{MAX as IMAX, MIN as IMIN}; |
| assert_eq!((0..0isize).size_hint(), (0, Some(0))); |
| assert_eq!((-100..100isize).size_hint(), (200, Some(200))); |
| assert_eq!((IMIN..IMAX).size_hint(), (UMAX, Some(UMAX))); |
| |
| let imin = i128::try_from(IMIN).unwrap(); |
| let imax = i128::try_from(IMAX).unwrap(); |
| assert_eq!((0..0i128).size_hint(), (0, Some(0))); |
| assert_eq!((-100..100i128).size_hint(), (200, Some(200))); |
| assert_eq!((imin..imax).size_hint(), (UMAX, Some(UMAX))); |
| assert_eq!((imin..imax + 1).size_hint(), (UMAX, None)); |
| } |
| |
| #[test] |
| fn test_range_inclusive_size_hint() { |
| use core::usize::MAX as UMAX; |
| assert_eq!((1..=0usize).size_hint(), (0, Some(0))); |
| assert_eq!((0..=0usize).size_hint(), (1, Some(1))); |
| assert_eq!((0..=100usize).size_hint(), (101, Some(101))); |
| assert_eq!((0..=UMAX - 1).size_hint(), (UMAX, Some(UMAX))); |
| assert_eq!((0..=UMAX).size_hint(), (UMAX, None)); |
| |
| let umax = u128::try_from(UMAX).unwrap(); |
| assert_eq!((1..=0u128).size_hint(), (0, Some(0))); |
| assert_eq!((0..=0u128).size_hint(), (1, Some(1))); |
| assert_eq!((0..=100u128).size_hint(), (101, Some(101))); |
| assert_eq!((0..=umax - 1).size_hint(), (UMAX, Some(UMAX))); |
| assert_eq!((0..=umax).size_hint(), (UMAX, None)); |
| assert_eq!((0..=umax + 1).size_hint(), (UMAX, None)); |
| |
| use core::isize::{MAX as IMAX, MIN as IMIN}; |
| assert_eq!((0..=-1isize).size_hint(), (0, Some(0))); |
| assert_eq!((0..=0isize).size_hint(), (1, Some(1))); |
| assert_eq!((-100..=100isize).size_hint(), (201, Some(201))); |
| assert_eq!((IMIN..=IMAX - 1).size_hint(), (UMAX, Some(UMAX))); |
| assert_eq!((IMIN..=IMAX).size_hint(), (UMAX, None)); |
| |
| let imin = i128::try_from(IMIN).unwrap(); |
| let imax = i128::try_from(IMAX).unwrap(); |
| assert_eq!((0..=-1i128).size_hint(), (0, Some(0))); |
| assert_eq!((0..=0i128).size_hint(), (1, Some(1))); |
| assert_eq!((-100..=100i128).size_hint(), (201, Some(201))); |
| assert_eq!((imin..=imax - 1).size_hint(), (UMAX, Some(UMAX))); |
| assert_eq!((imin..=imax).size_hint(), (UMAX, None)); |
| assert_eq!((imin..=imax + 1).size_hint(), (UMAX, None)); |
| } |
| |
| #[test] |
| fn test_repeat() { |
| let mut it = repeat(42); |
| assert_eq!(it.next(), Some(42)); |
| assert_eq!(it.next(), Some(42)); |
| assert_eq!(it.next(), Some(42)); |
| assert_eq!(repeat(42).size_hint(), (usize::MAX, None)); |
| } |
| |
| #[test] |
| fn test_repeat_take() { |
| let mut it = repeat(42).take(3); |
| assert_eq!(it.next(), Some(42)); |
| assert_eq!(it.next(), Some(42)); |
| assert_eq!(it.next(), Some(42)); |
| assert_eq!(it.next(), None); |
| is_trusted_len(repeat(42).take(3)); |
| assert_eq!(repeat(42).take(3).size_hint(), (3, Some(3))); |
| assert_eq!(repeat(42).take(0).size_hint(), (0, Some(0))); |
| assert_eq!(repeat(42).take(usize::MAX).size_hint(), (usize::MAX, Some(usize::MAX))); |
| } |
| |
| #[test] |
| fn test_repeat_take_collect() { |
| let v: Vec<_> = repeat(42).take(3).collect(); |
| assert_eq!(v, vec![42, 42, 42]); |
| } |
| |
| #[test] |
| fn test_repeat_with() { |
| #[derive(PartialEq, Debug)] |
| struct NotClone(usize); |
| let mut it = repeat_with(|| NotClone(42)); |
| assert_eq!(it.next(), Some(NotClone(42))); |
| assert_eq!(it.next(), Some(NotClone(42))); |
| assert_eq!(it.next(), Some(NotClone(42))); |
| assert_eq!(repeat_with(|| NotClone(42)).size_hint(), (usize::MAX, None)); |
| } |
| |
| #[test] |
| fn test_repeat_with_take() { |
| let mut it = repeat_with(|| 42).take(3); |
| assert_eq!(it.next(), Some(42)); |
| assert_eq!(it.next(), Some(42)); |
| assert_eq!(it.next(), Some(42)); |
| assert_eq!(it.next(), None); |
| is_trusted_len(repeat_with(|| 42).take(3)); |
| assert_eq!(repeat_with(|| 42).take(3).size_hint(), (3, Some(3))); |
| assert_eq!(repeat_with(|| 42).take(0).size_hint(), (0, Some(0))); |
| assert_eq!(repeat_with(|| 42).take(usize::MAX).size_hint(), |
| (usize::MAX, Some(usize::MAX))); |
| } |
| |
| #[test] |
| fn test_repeat_with_take_collect() { |
| let mut curr = 1; |
| let v: Vec<_> = repeat_with(|| { let tmp = curr; curr *= 2; tmp }) |
| .take(5).collect(); |
| assert_eq!(v, vec![1, 2, 4, 8, 16]); |
| } |
| |
| #[test] |
| fn test_successors() { |
| let mut powers_of_10 = successors(Some(1_u16), |n| n.checked_mul(10)); |
| assert_eq!(powers_of_10.by_ref().collect::<Vec<_>>(), &[1, 10, 100, 1_000, 10_000]); |
| assert_eq!(powers_of_10.next(), None); |
| |
| let mut empty = successors(None::<u32>, |_| unimplemented!()); |
| assert_eq!(empty.next(), None); |
| assert_eq!(empty.next(), None); |
| } |
| |
| #[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); |
| } |
| |
| #[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_once() { |
| let mut it = once(42); |
| assert_eq!(it.next(), Some(42)); |
| assert_eq!(it.next(), None); |
| } |
| |
| #[test] |
| fn test_once_with() { |
| let count = Cell::new(0); |
| let mut it = once_with(|| { |
| count.set(count.get() + 1); |
| 42 |
| }); |
| |
| assert_eq!(count.get(), 0); |
| assert_eq!(it.next(), Some(42)); |
| assert_eq!(count.get(), 1); |
| assert_eq!(it.next(), None); |
| assert_eq!(count.get(), 1); |
| assert_eq!(it.next(), None); |
| assert_eq!(count.get(), 1); |
| } |
| |
| #[test] |
| fn test_empty() { |
| let mut it = empty::<i32>(); |
| assert_eq!(it.next(), 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_step_replace_unsigned() { |
| let mut x = 4u32; |
| let y = x.replace_zero(); |
| assert_eq!(x, 0); |
| assert_eq!(y, 4); |
| |
| x = 5; |
| let y = x.replace_one(); |
| assert_eq!(x, 1); |
| assert_eq!(y, 5); |
| } |
| |
| #[test] |
| fn test_step_replace_signed() { |
| let mut x = 4i32; |
| let y = x.replace_zero(); |
| assert_eq!(x, 0); |
| assert_eq!(y, 4); |
| |
| x = 5; |
| let y = x.replace_one(); |
| assert_eq!(x, 1); |
| assert_eq!(y, 5); |
| } |
| |
| #[test] |
| fn test_step_replace_no_between() { |
| let mut x = 4u128; |
| let y = x.replace_zero(); |
| assert_eq!(x, 0); |
| assert_eq!(y, 4); |
| |
| x = 5; |
| let y = x.replace_one(); |
| assert_eq!(x, 1); |
| assert_eq!(y, 5); |
| } |
| |
| #[test] |
| fn test_rev_try_folds() { |
| let f = &|acc, x| i32::checked_add(2*acc, x); |
| assert_eq!((1..10).rev().try_fold(7, f), (1..10).try_rfold(7, f)); |
| assert_eq!((1..10).rev().try_rfold(7, f), (1..10).try_fold(7, f)); |
| |
| let a = [10, 20, 30, 40, 100, 60, 70, 80, 90]; |
| let mut iter = a.iter().rev(); |
| assert_eq!(iter.try_fold(0_i8, |acc, &x| acc.checked_add(x)), None); |
| assert_eq!(iter.next(), Some(&70)); |
| let mut iter = a.iter().rev(); |
| assert_eq!(iter.try_rfold(0_i8, |acc, &x| acc.checked_add(x)), None); |
| assert_eq!(iter.next_back(), Some(&60)); |
| } |
| |
| #[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)); |
| } |
| |
| #[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_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_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_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_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_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_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)); |
| } |
| |
| #[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)); |
| } |
| |
| #[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_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(())); |
| } |
| |
| #[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_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_functor_laws() { |
| // identity: |
| fn identity<T>(x: T) -> T { x } |
| assert_eq!((0..10).map(identity).sum::<usize>(), (0..10).sum()); |
| |
| // composition: |
| fn f(x: usize) -> usize { x + 3 } |
| fn g(x: usize) -> usize { x * 2 } |
| fn h(x: usize) -> usize { g(f(x)) } |
| assert_eq!((0..10).map(f).map(g).sum::<usize>(), (0..10).map(h).sum()); |
| } |
| |
| #[test] |
| fn test_monad_laws_left_identity() { |
| fn f(x: usize) -> impl Iterator<Item = usize> { |
| (0..10).map(move |y| x * y) |
| } |
| assert_eq!(once(42).flat_map(f.clone()).sum::<usize>(), f(42).sum()); |
| } |
| |
| #[test] |
| fn test_monad_laws_right_identity() { |
| assert_eq!((0..10).flat_map(|x| once(x)).sum::<usize>(), (0..10).sum()); |
| } |
| |
| #[test] |
| fn test_monad_laws_associativity() { |
| fn f(x: usize) -> impl Iterator<Item = usize> { 0..x } |
| fn g(x: usize) -> impl Iterator<Item = usize> { (0..x).rev() } |
| assert_eq!((0..10).flat_map(f).flat_map(g).sum::<usize>(), |
| (0..10).flat_map(|x| f(x).flat_map(g)).sum::<usize>()); |
| } |
| |
| #[test] |
| fn test_is_sorted() { |
| assert!([1, 2, 2, 9].iter().is_sorted()); |
| assert!(![1, 3, 2].iter().is_sorted()); |
| assert!([0].iter().is_sorted()); |
| assert!(std::iter::empty::<i32>().is_sorted()); |
| assert!(![0.0, 1.0, std::f32::NAN].iter().is_sorted()); |
| assert!([-2, -1, 0, 3].iter().is_sorted()); |
| assert!(![-2i32, -1, 0, 3].iter().is_sorted_by_key(|n| n.abs())); |
| assert!(!["c", "bb", "aaa"].iter().is_sorted()); |
| assert!(["c", "bb", "aaa"].iter().is_sorted_by_key(|s| s.len())); |
| } |
| |
| #[test] |
| fn test_partition() { |
| fn check(xs: &mut [i32], ref p: impl Fn(&i32) -> bool, expected: usize) { |
| let i = xs.iter_mut().partition_in_place(p); |
| assert_eq!(expected, i); |
| assert!(xs[..i].iter().all(p)); |
| assert!(!xs[i..].iter().any(p)); |
| assert!(xs.iter().is_partitioned(p)); |
| if i == 0 || i == xs.len() { |
| assert!(xs.iter().rev().is_partitioned(p)); |
| } else { |
| assert!(!xs.iter().rev().is_partitioned(p)); |
| } |
| } |
| |
| check(&mut [], |_| true, 0); |
| check(&mut [], |_| false, 0); |
| |
| check(&mut [0], |_| true, 1); |
| check(&mut [0], |_| false, 0); |
| |
| check(&mut [-1, 1], |&x| x > 0, 1); |
| check(&mut [-1, 1], |&x| x < 0, 1); |
| |
| let ref mut xs = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]; |
| check(xs, |_| true, 10); |
| check(xs, |_| false, 0); |
| check(xs, |&x| x % 2 == 0, 5); // evens |
| check(xs, |&x| x % 2 == 1, 5); // odds |
| check(xs, |&x| x % 3 == 0, 4); // multiple of 3 |
| check(xs, |&x| x % 4 == 0, 3); // multiple of 4 |
| check(xs, |&x| x % 5 == 0, 2); // multiple of 5 |
| check(xs, |&x| x < 3, 3); // small |
| check(xs, |&x| x > 6, 3); // large |
| } |