1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
12 use core::{i8, i16, isize};
17 let empty: [isize; 0] = [];
21 assert!(!xs.iter().lt(ys.iter()));
22 assert!(!xs.iter().le(ys.iter()));
23 assert!( xs.iter().gt(ys.iter()));
24 assert!( xs.iter().ge(ys.iter()));
26 assert!( ys.iter().lt(xs.iter()));
27 assert!( ys.iter().le(xs.iter()));
28 assert!(!ys.iter().gt(xs.iter()));
29 assert!(!ys.iter().ge(xs.iter()));
31 assert!( empty.iter().lt(xs.iter()));
32 assert!( empty.iter().le(xs.iter()));
33 assert!(!empty.iter().gt(xs.iter()));
34 assert!(!empty.iter().ge(xs.iter()));
37 let u = [1.0f64, 2.0];
38 let v = [0.0f64/0.0, 3.0];
40 assert!(!u.iter().lt(v.iter()));
41 assert!(!u.iter().le(v.iter()));
42 assert!(!u.iter().gt(v.iter()));
43 assert!(!u.iter().ge(v.iter()));
49 assert!(a.iter().lt(b.iter()) == (a[0] < b[0]));
50 assert!(a.iter().le(b.iter()) == (a[0] <= b[0]));
51 assert!(a.iter().gt(b.iter()) == (a[0] > b[0]));
52 assert!(a.iter().ge(b.iter()) == (a[0] >= b[0]));
54 assert!(c.iter().lt(b.iter()) == (c[0] < b[0]));
55 assert!(c.iter().le(b.iter()) == (c[0] <= b[0]));
56 assert!(c.iter().gt(b.iter()) == (c[0] > b[0]));
57 assert!(c.iter().ge(b.iter()) == (c[0] >= b[0]));
61 fn test_multi_iter() {
64 assert!(xs.iter().eq(ys.iter().rev()));
65 assert!(xs.iter().lt(xs.iter().skip(2)));
69 fn test_counter_from_iter() {
70 let it = (0..).step_by(5).take(10);
71 let xs: Vec<isize> = FromIterator::from_iter(it);
72 assert_eq!(xs, [0, 5, 10, 15, 20, 25, 30, 35, 40, 45]);
76 fn test_iterator_chain() {
77 let xs = [0, 1, 2, 3, 4, 5];
78 let ys = [30, 40, 50, 60];
79 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
80 let it = xs.iter().chain(&ys);
83 assert_eq!(x, expected[i]);
86 assert_eq!(i, expected.len());
88 let ys = (30..).step_by(10).take(4);
89 let it = xs.iter().cloned().chain(ys);
92 assert_eq!(x, expected[i]);
95 assert_eq!(i, expected.len());
99 fn test_iterator_chain_nth() {
100 let xs = [0, 1, 2, 3, 4, 5];
101 let ys = [30, 40, 50, 60];
103 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
104 for (i, x) in expected.iter().enumerate() {
105 assert_eq!(Some(x), xs.iter().chain(&ys).nth(i));
107 assert_eq!(zs.iter().chain(&xs).nth(0), Some(&0));
109 let mut it = xs.iter().chain(&zs);
110 assert_eq!(it.nth(5), Some(&5));
111 assert_eq!(it.next(), None);
115 fn test_iterator_chain_last() {
116 let xs = [0, 1, 2, 3, 4, 5];
117 let ys = [30, 40, 50, 60];
119 assert_eq!(xs.iter().chain(&ys).last(), Some(&60));
120 assert_eq!(zs.iter().chain(&ys).last(), Some(&60));
121 assert_eq!(ys.iter().chain(&zs).last(), Some(&60));
122 assert_eq!(zs.iter().chain(&zs).last(), None);
126 fn test_iterator_chain_count() {
127 let xs = [0, 1, 2, 3, 4, 5];
128 let ys = [30, 40, 50, 60];
130 assert_eq!(xs.iter().chain(&ys).count(), 10);
131 assert_eq!(zs.iter().chain(&ys).count(), 4);
135 fn test_iterator_chain_find() {
136 let xs = [0, 1, 2, 3, 4, 5];
137 let ys = [30, 40, 50, 60];
138 let mut iter = xs.iter().chain(&ys);
139 assert_eq!(iter.find(|&&i| i == 4), Some(&4));
140 assert_eq!(iter.next(), Some(&5));
141 assert_eq!(iter.find(|&&i| i == 40), Some(&40));
142 assert_eq!(iter.next(), Some(&50));
143 assert_eq!(iter.find(|&&i| i == 100), None);
144 assert_eq!(iter.next(), None);
148 fn test_iterator_step_by() {
150 let mut it = (0..).step_by(1).take(3);
151 assert_eq!(it.next(), Some(0));
152 assert_eq!(it.next(), Some(1));
153 assert_eq!(it.next(), Some(2));
154 assert_eq!(it.next(), None);
156 let mut it = (0..).step_by(3).take(4);
157 assert_eq!(it.next(), Some(0));
158 assert_eq!(it.next(), Some(3));
159 assert_eq!(it.next(), Some(6));
160 assert_eq!(it.next(), Some(9));
161 assert_eq!(it.next(), None);
165 fn test_iterator_step_by_nth() {
166 let mut it = (0..16).step_by(5);
167 assert_eq!(it.nth(0), Some(0));
168 assert_eq!(it.nth(0), Some(5));
169 assert_eq!(it.nth(0), Some(10));
170 assert_eq!(it.nth(0), Some(15));
171 assert_eq!(it.nth(0), None);
173 let it = (0..18).step_by(5);
174 assert_eq!(it.clone().nth(0), Some(0));
175 assert_eq!(it.clone().nth(1), Some(5));
176 assert_eq!(it.clone().nth(2), Some(10));
177 assert_eq!(it.clone().nth(3), Some(15));
178 assert_eq!(it.clone().nth(4), None);
179 assert_eq!(it.clone().nth(42), None);
183 fn test_iterator_step_by_nth_overflow() {
184 #[cfg(target_pointer_width = "8")]
186 #[cfg(target_pointer_width = "16")]
188 #[cfg(target_pointer_width = "32")]
190 #[cfg(target_pointer_width = "64")]
195 impl<'a> Iterator for &'a mut Test {
197 fn next(&mut self) -> Option<Self::Item> { Some(21) }
198 fn nth(&mut self, n: usize) -> Option<Self::Item> {
199 self.0 += n as Bigger + 1;
204 let mut it = Test(0);
205 let root = usize::MAX >> (::std::mem::size_of::<usize>() * 8 / 2);
207 (&mut it).step_by(n).nth(n);
208 assert_eq!(it.0, n as Bigger * n as Bigger);
211 let mut it = Test(0);
212 (&mut it).step_by(usize::MAX).nth(5);
213 assert_eq!(it.0, (usize::MAX as Bigger) * 5);
216 let mut it = Test(0);
217 (&mut it).step_by(2).nth(usize::MAX);
218 assert_eq!(it.0, (usize::MAX as Bigger) * 2);
221 let mut it = Test(0);
222 (&mut it).step_by(1).nth(usize::MAX);
223 assert_eq!(it.0, (usize::MAX as Bigger) * 1);
228 fn test_iterator_step_by_zero() {
229 let mut it = (0..).step_by(0);
234 fn test_iterator_step_by_size_hint() {
235 struct StubSizeHint(usize, Option<usize>);
236 impl Iterator for StubSizeHint {
238 fn next(&mut self) -> Option<()> {
240 if let Some(ref mut upper) = self.1 {
245 fn size_hint(&self) -> (usize, Option<usize>) {
250 // The two checks in each case are needed because the logic
251 // is different before the first call to `next()`.
253 let mut it = StubSizeHint(10, Some(10)).step_by(1);
254 assert_eq!(it.size_hint(), (10, Some(10)));
256 assert_eq!(it.size_hint(), (9, Some(9)));
259 let mut it = StubSizeHint(10, Some(10)).step_by(3);
260 assert_eq!(it.size_hint(), (4, Some(4)));
262 assert_eq!(it.size_hint(), (3, Some(3)));
264 // larger base range, but not enough to get another element
265 let mut it = StubSizeHint(12, Some(12)).step_by(3);
266 assert_eq!(it.size_hint(), (4, Some(4)));
268 assert_eq!(it.size_hint(), (3, Some(3)));
270 // smaller base range, so fewer resulting elements
271 let mut it = StubSizeHint(9, Some(9)).step_by(3);
272 assert_eq!(it.size_hint(), (3, Some(3)));
274 assert_eq!(it.size_hint(), (2, Some(2)));
276 // infinite upper bound
277 let mut it = StubSizeHint(usize::MAX, None).step_by(1);
278 assert_eq!(it.size_hint(), (usize::MAX, None));
280 assert_eq!(it.size_hint(), (usize::MAX-1, None));
282 // still infinite with larger step
283 let mut it = StubSizeHint(7, None).step_by(3);
284 assert_eq!(it.size_hint(), (3, None));
286 assert_eq!(it.size_hint(), (2, None));
288 // propagates ExactSizeIterator
290 let it = a.iter().step_by(2);
291 assert_eq!(it.len(), 3);
293 // Cannot be TrustedLen as a step greater than one makes an iterator
294 // with (usize::MAX, None) no longer meet the safety requirements
295 trait TrustedLenCheck { fn test(self) -> bool; }
296 impl<T:Iterator> TrustedLenCheck for T {
297 default fn test(self) -> bool { false }
299 impl<T:TrustedLen> TrustedLenCheck for T {
300 fn test(self) -> bool { true }
302 assert!(TrustedLenCheck::test(a.iter()));
303 assert!(!TrustedLenCheck::test(a.iter().step_by(1)));
307 fn test_filter_map() {
308 let it = (0..).step_by(1).take(10)
309 .filter_map(|x| if x % 2 == 0 { Some(x*x) } else { None });
310 assert_eq!(it.collect::<Vec<usize>>(), [0*0, 2*2, 4*4, 6*6, 8*8]);
314 fn test_filter_map_fold() {
315 let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8];
316 let ys = [0*0, 2*2, 4*4, 6*6, 8*8];
317 let it = xs.iter().filter_map(|&x| if x % 2 == 0 { Some(x*x) } else { None });
318 let i = it.fold(0, |i, x| {
319 assert_eq!(x, ys[i]);
322 assert_eq!(i, ys.len());
324 let it = xs.iter().filter_map(|&x| if x % 2 == 0 { Some(x*x) } else { None });
325 let i = it.rfold(ys.len(), |i, x| {
326 assert_eq!(x, ys[i - 1]);
333 fn test_iterator_enumerate() {
334 let xs = [0, 1, 2, 3, 4, 5];
335 let it = xs.iter().enumerate();
342 fn test_iterator_enumerate_nth() {
343 let xs = [0, 1, 2, 3, 4, 5];
344 for (i, &x) in xs.iter().enumerate() {
348 let mut it = xs.iter().enumerate();
349 while let Some((i, &x)) = it.nth(0) {
353 let mut it = xs.iter().enumerate();
354 while let Some((i, &x)) = it.nth(1) {
358 let (i, &x) = xs.iter().enumerate().nth(3).unwrap();
364 fn test_iterator_enumerate_count() {
365 let xs = [0, 1, 2, 3, 4, 5];
366 assert_eq!(xs.iter().enumerate().count(), 6);
370 fn test_iterator_enumerate_fold() {
371 let xs = [0, 1, 2, 3, 4, 5];
372 let mut it = xs.iter().enumerate();
373 // steal a couple to get an interesting offset
374 assert_eq!(it.next(), Some((0, &0)));
375 assert_eq!(it.next(), Some((1, &1)));
376 let i = it.fold(2, |i, (j, &x)| {
378 assert_eq!(x, xs[j]);
381 assert_eq!(i, xs.len());
383 let mut it = xs.iter().enumerate();
384 assert_eq!(it.next(), Some((0, &0)));
385 let i = it.rfold(xs.len() - 1, |i, (j, &x)| {
387 assert_eq!(x, xs[j]);
394 fn test_iterator_filter_count() {
395 let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8];
396 assert_eq!(xs.iter().filter(|&&x| x % 2 == 0).count(), 5);
400 fn test_iterator_filter_fold() {
401 let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8];
402 let ys = [0, 2, 4, 6, 8];
403 let it = xs.iter().filter(|&&x| x % 2 == 0);
404 let i = it.fold(0, |i, &x| {
405 assert_eq!(x, ys[i]);
408 assert_eq!(i, ys.len());
410 let it = xs.iter().filter(|&&x| x % 2 == 0);
411 let i = it.rfold(ys.len(), |i, &x| {
412 assert_eq!(x, ys[i - 1]);
419 fn test_iterator_peekable() {
420 let xs = vec![0, 1, 2, 3, 4, 5];
421 let mut it = xs.iter().cloned().peekable();
423 assert_eq!(it.len(), 6);
424 assert_eq!(it.peek().unwrap(), &0);
425 assert_eq!(it.len(), 6);
426 assert_eq!(it.next().unwrap(), 0);
427 assert_eq!(it.len(), 5);
428 assert_eq!(it.next().unwrap(), 1);
429 assert_eq!(it.len(), 4);
430 assert_eq!(it.next().unwrap(), 2);
431 assert_eq!(it.len(), 3);
432 assert_eq!(it.peek().unwrap(), &3);
433 assert_eq!(it.len(), 3);
434 assert_eq!(it.peek().unwrap(), &3);
435 assert_eq!(it.len(), 3);
436 assert_eq!(it.next().unwrap(), 3);
437 assert_eq!(it.len(), 2);
438 assert_eq!(it.next().unwrap(), 4);
439 assert_eq!(it.len(), 1);
440 assert_eq!(it.peek().unwrap(), &5);
441 assert_eq!(it.len(), 1);
442 assert_eq!(it.next().unwrap(), 5);
443 assert_eq!(it.len(), 0);
444 assert!(it.peek().is_none());
445 assert_eq!(it.len(), 0);
446 assert!(it.next().is_none());
447 assert_eq!(it.len(), 0);
451 fn test_iterator_peekable_count() {
452 let xs = [0, 1, 2, 3, 4, 5];
454 let zs: [i32; 0] = [];
456 assert_eq!(xs.iter().peekable().count(), 6);
458 let mut it = xs.iter().peekable();
459 assert_eq!(it.peek(), Some(&&0));
460 assert_eq!(it.count(), 6);
462 assert_eq!(ys.iter().peekable().count(), 1);
464 let mut it = ys.iter().peekable();
465 assert_eq!(it.peek(), Some(&&10));
466 assert_eq!(it.count(), 1);
468 assert_eq!(zs.iter().peekable().count(), 0);
470 let mut it = zs.iter().peekable();
471 assert_eq!(it.peek(), None);
476 fn test_iterator_peekable_nth() {
477 let xs = [0, 1, 2, 3, 4, 5];
478 let mut it = xs.iter().peekable();
480 assert_eq!(it.peek(), Some(&&0));
481 assert_eq!(it.nth(0), Some(&0));
482 assert_eq!(it.peek(), Some(&&1));
483 assert_eq!(it.nth(1), Some(&2));
484 assert_eq!(it.peek(), Some(&&3));
485 assert_eq!(it.nth(2), Some(&5));
486 assert_eq!(it.next(), None);
490 fn test_iterator_peekable_last() {
491 let xs = [0, 1, 2, 3, 4, 5];
494 let mut it = xs.iter().peekable();
495 assert_eq!(it.peek(), Some(&&0));
496 assert_eq!(it.last(), Some(&5));
498 let mut it = ys.iter().peekable();
499 assert_eq!(it.peek(), Some(&&0));
500 assert_eq!(it.last(), Some(&0));
502 let mut it = ys.iter().peekable();
503 assert_eq!(it.next(), Some(&0));
504 assert_eq!(it.peek(), None);
505 assert_eq!(it.last(), None);
509 fn test_iterator_peekable_fold() {
510 let xs = [0, 1, 2, 3, 4, 5];
511 let mut it = xs.iter().peekable();
512 assert_eq!(it.peek(), Some(&&0));
513 let i = it.fold(0, |i, &x| {
514 assert_eq!(x, xs[i]);
517 assert_eq!(i, xs.len());
520 /// This is an iterator that follows the Iterator contract,
521 /// but it is not fused. After having returned None once, it will start
522 /// producing elements if .next() is called again.
523 pub struct CycleIter<'a, T: 'a> {
528 pub fn cycle<T>(data: &[T]) -> CycleIter<T> {
535 impl<'a, T> Iterator for CycleIter<'a, T> {
537 fn next(&mut self) -> Option<Self::Item> {
538 let elt = self.data.get(self.index);
540 self.index %= 1 + self.data.len();
546 fn test_iterator_peekable_remember_peek_none_1() {
547 // Check that the loop using .peek() terminates
548 let data = [1, 2, 3];
549 let mut iter = cycle(&data).peekable();
552 while let Some(_) = iter.next() {
553 let is_the_last = iter.peek().is_none();
554 assert_eq!(is_the_last, n == data.len() - 1);
556 if n > data.len() { break; }
558 assert_eq!(n, data.len());
562 fn test_iterator_peekable_remember_peek_none_2() {
564 let mut iter = cycle(&data).peekable();
566 assert_eq!(iter.peek(), None);
567 assert_eq!(iter.last(), None);
571 fn test_iterator_peekable_remember_peek_none_3() {
573 let mut iter = cycle(&data).peekable();
575 assert_eq!(iter.nth(0), Some(&0));
577 let mut iter = cycle(&data).peekable();
579 assert_eq!(iter.peek(), None);
580 assert_eq!(iter.nth(0), None);
584 fn test_iterator_take_while() {
585 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
586 let ys = [0, 1, 2, 3, 5, 13];
587 let it = xs.iter().take_while(|&x| *x < 15);
590 assert_eq!(*x, ys[i]);
593 assert_eq!(i, ys.len());
597 fn test_iterator_skip_while() {
598 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
599 let ys = [15, 16, 17, 19];
600 let it = xs.iter().skip_while(|&x| *x < 15);
603 assert_eq!(*x, ys[i]);
606 assert_eq!(i, ys.len());
610 fn test_iterator_skip_while_fold() {
611 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
612 let ys = [15, 16, 17, 19];
613 let it = xs.iter().skip_while(|&x| *x < 15);
614 let i = it.fold(0, |i, &x| {
615 assert_eq!(x, ys[i]);
618 assert_eq!(i, ys.len());
620 let mut it = xs.iter().skip_while(|&x| *x < 15);
621 assert_eq!(it.next(), Some(&ys[0])); // process skips before folding
622 let i = it.fold(1, |i, &x| {
623 assert_eq!(x, ys[i]);
626 assert_eq!(i, ys.len());
630 fn test_iterator_skip() {
631 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
632 let ys = [13, 15, 16, 17, 19, 20, 30];
633 let mut it = xs.iter().skip(5);
635 while let Some(&x) = it.next() {
636 assert_eq!(x, ys[i]);
638 assert_eq!(it.len(), xs.len()-5-i);
640 assert_eq!(i, ys.len());
641 assert_eq!(it.len(), 0);
645 fn test_iterator_skip_doubleended() {
646 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
647 let mut it = xs.iter().rev().skip(5);
648 assert_eq!(it.next(), Some(&15));
649 assert_eq!(it.by_ref().rev().next(), Some(&0));
650 assert_eq!(it.next(), Some(&13));
651 assert_eq!(it.by_ref().rev().next(), Some(&1));
652 assert_eq!(it.next(), Some(&5));
653 assert_eq!(it.by_ref().rev().next(), Some(&2));
654 assert_eq!(it.next(), Some(&3));
655 assert_eq!(it.next(), None);
656 let mut it = xs.iter().rev().skip(5).rev();
657 assert_eq!(it.next(), Some(&0));
658 assert_eq!(it.rev().next(), Some(&15));
659 let mut it_base = xs.iter();
661 let mut it = it_base.by_ref().skip(5).rev();
662 assert_eq!(it.next(), Some(&30));
663 assert_eq!(it.next(), Some(&20));
664 assert_eq!(it.next(), Some(&19));
665 assert_eq!(it.next(), Some(&17));
666 assert_eq!(it.next(), Some(&16));
667 assert_eq!(it.next(), Some(&15));
668 assert_eq!(it.next(), Some(&13));
669 assert_eq!(it.next(), None);
671 // make sure the skipped parts have not been consumed
672 assert_eq!(it_base.next(), Some(&0));
673 assert_eq!(it_base.next(), Some(&1));
674 assert_eq!(it_base.next(), Some(&2));
675 assert_eq!(it_base.next(), Some(&3));
676 assert_eq!(it_base.next(), Some(&5));
677 assert_eq!(it_base.next(), None);
678 let it = xs.iter().skip(5).rev();
679 assert_eq!(it.last(), Some(&13));
683 fn test_iterator_skip_nth() {
684 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
686 let mut it = xs.iter().skip(0);
687 assert_eq!(it.nth(0), Some(&0));
688 assert_eq!(it.nth(1), Some(&2));
690 let mut it = xs.iter().skip(5);
691 assert_eq!(it.nth(0), Some(&13));
692 assert_eq!(it.nth(1), Some(&16));
694 let mut it = xs.iter().skip(12);
695 assert_eq!(it.nth(0), None);
700 fn test_iterator_skip_count() {
701 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
703 assert_eq!(xs.iter().skip(0).count(), 12);
704 assert_eq!(xs.iter().skip(1).count(), 11);
705 assert_eq!(xs.iter().skip(11).count(), 1);
706 assert_eq!(xs.iter().skip(12).count(), 0);
707 assert_eq!(xs.iter().skip(13).count(), 0);
711 fn test_iterator_skip_last() {
712 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
714 assert_eq!(xs.iter().skip(0).last(), Some(&30));
715 assert_eq!(xs.iter().skip(1).last(), Some(&30));
716 assert_eq!(xs.iter().skip(11).last(), Some(&30));
717 assert_eq!(xs.iter().skip(12).last(), None);
718 assert_eq!(xs.iter().skip(13).last(), None);
720 let mut it = xs.iter().skip(5);
721 assert_eq!(it.next(), Some(&13));
722 assert_eq!(it.last(), Some(&30));
726 fn test_iterator_skip_fold() {
727 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
728 let ys = [13, 15, 16, 17, 19, 20, 30];
730 let it = xs.iter().skip(5);
731 let i = it.fold(0, |i, &x| {
732 assert_eq!(x, ys[i]);
735 assert_eq!(i, ys.len());
737 let mut it = xs.iter().skip(5);
738 assert_eq!(it.next(), Some(&ys[0])); // process skips before folding
739 let i = it.fold(1, |i, &x| {
740 assert_eq!(x, ys[i]);
743 assert_eq!(i, ys.len());
745 let it = xs.iter().skip(5);
746 let i = it.rfold(ys.len(), |i, &x| {
748 assert_eq!(x, ys[i]);
753 let mut it = xs.iter().skip(5);
754 assert_eq!(it.next(), Some(&ys[0])); // process skips before folding
755 let i = it.rfold(ys.len(), |i, &x| {
757 assert_eq!(x, ys[i]);
765 fn test_iterator_take() {
766 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
767 let ys = [0, 1, 2, 3, 5];
768 let mut it = xs.iter().take(5);
770 assert_eq!(it.len(), 5);
771 while let Some(&x) = it.next() {
772 assert_eq!(x, ys[i]);
774 assert_eq!(it.len(), 5-i);
776 assert_eq!(i, ys.len());
777 assert_eq!(it.len(), 0);
781 fn test_iterator_take_nth() {
782 let xs = [0, 1, 2, 4, 5];
783 let mut it = xs.iter();
785 let mut take = it.by_ref().take(3);
787 while let Some(&x) = take.nth(0) {
792 assert_eq!(it.nth(1), Some(&5));
793 assert_eq!(it.nth(0), None);
795 let xs = [0, 1, 2, 3, 4];
796 let mut it = xs.iter().take(7);
798 while let Some(&x) = it.nth(1) {
805 fn test_iterator_take_short() {
806 let xs = [0, 1, 2, 3];
807 let ys = [0, 1, 2, 3];
808 let mut it = xs.iter().take(5);
810 assert_eq!(it.len(), 4);
811 while let Some(&x) = it.next() {
812 assert_eq!(x, ys[i]);
814 assert_eq!(it.len(), 4-i);
816 assert_eq!(i, ys.len());
817 assert_eq!(it.len(), 0);
821 fn test_iterator_scan() {
822 // test the type inference
823 fn add(old: &mut isize, new: &usize) -> Option<f64> {
824 *old += *new as isize;
827 let xs = [0, 1, 2, 3, 4];
828 let ys = [0f64, 1.0, 3.0, 6.0, 10.0];
830 let it = xs.iter().scan(0, add);
833 assert_eq!(x, ys[i]);
836 assert_eq!(i, ys.len());
840 fn test_iterator_flat_map() {
842 let ys = [0, 1, 2, 3, 4, 5, 6, 7, 8];
843 let it = xs.iter().flat_map(|&x| (x..).step_by(1).take(3));
846 assert_eq!(x, ys[i]);
849 assert_eq!(i, ys.len());
852 /// Test `FlatMap::fold` with items already picked off the front and back,
853 /// to make sure all parts of the `FlatMap` are folded correctly.
855 fn test_iterator_flat_map_fold() {
857 let ys = [1, 2, 3, 4, 5, 6, 7];
858 let mut it = xs.iter().flat_map(|&x| x..x+3);
859 assert_eq!(it.next(), Some(0));
860 assert_eq!(it.next_back(), Some(8));
861 let i = it.fold(0, |i, x| {
862 assert_eq!(x, ys[i]);
865 assert_eq!(i, ys.len());
867 let mut it = xs.iter().flat_map(|&x| x..x+3);
868 assert_eq!(it.next(), Some(0));
869 assert_eq!(it.next_back(), Some(8));
870 let i = it.rfold(ys.len(), |i, x| {
871 assert_eq!(x, ys[i - 1]);
879 let xs = [1, 2, 3, 4];
885 .collect::<Vec<usize>>();
887 assert_eq!(n, xs.len());
888 assert_eq!(&xs[..], &ys[..]);
892 fn test_inspect_fold() {
893 let xs = [1, 2, 3, 4];
896 let it = xs.iter().inspect(|_| n += 1);
897 let i = it.fold(0, |i, &x| {
898 assert_eq!(x, xs[i]);
901 assert_eq!(i, xs.len());
903 assert_eq!(n, xs.len());
907 let it = xs.iter().inspect(|_| n += 1);
908 let i = it.rfold(xs.len(), |i, &x| {
909 assert_eq!(x, xs[i - 1]);
914 assert_eq!(n, xs.len());
920 let it = (0..).step_by(1).take(cycle_len).cycle();
921 assert_eq!(it.size_hint(), (usize::MAX, None));
922 for (i, x) in it.take(100).enumerate() {
923 assert_eq!(i % cycle_len, x);
926 let mut it = (0..).step_by(1).take(0).cycle();
927 assert_eq!(it.size_hint(), (0, Some(0)));
928 assert_eq!(it.next(), None);
932 fn test_iterator_nth() {
933 let v: &[_] = &[0, 1, 2, 3, 4];
934 for i in 0..v.len() {
935 assert_eq!(v.iter().nth(i).unwrap(), &v[i]);
937 assert_eq!(v.iter().nth(v.len()), None);
941 fn test_iterator_last() {
942 let v: &[_] = &[0, 1, 2, 3, 4];
943 assert_eq!(v.iter().last().unwrap(), &4);
944 assert_eq!(v[..1].iter().last().unwrap(), &0);
948 fn test_iterator_len() {
949 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
950 assert_eq!(v[..4].iter().count(), 4);
951 assert_eq!(v[..10].iter().count(), 10);
952 assert_eq!(v[..0].iter().count(), 0);
956 fn test_iterator_sum() {
957 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
958 assert_eq!(v[..4].iter().cloned().sum::<i32>(), 6);
959 assert_eq!(v.iter().cloned().sum::<i32>(), 55);
960 assert_eq!(v[..0].iter().cloned().sum::<i32>(), 0);
964 fn test_iterator_sum_result() {
965 let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)];
966 assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Ok(10));
967 let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)];
968 assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Err(()));
972 fn test_iterator_product() {
973 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
974 assert_eq!(v[..4].iter().cloned().product::<i32>(), 0);
975 assert_eq!(v[1..5].iter().cloned().product::<i32>(), 24);
976 assert_eq!(v[..0].iter().cloned().product::<i32>(), 1);
980 fn test_iterator_product_result() {
981 let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)];
982 assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Ok(24));
983 let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)];
984 assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Err(()));
988 fn test_iterator_max() {
989 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
990 assert_eq!(v[..4].iter().cloned().max(), Some(3));
991 assert_eq!(v.iter().cloned().max(), Some(10));
992 assert_eq!(v[..0].iter().cloned().max(), None);
996 fn test_iterator_min() {
997 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
998 assert_eq!(v[..4].iter().cloned().min(), Some(0));
999 assert_eq!(v.iter().cloned().min(), Some(0));
1000 assert_eq!(v[..0].iter().cloned().min(), None);
1004 fn test_iterator_size_hint() {
1005 let c = (0..).step_by(1);
1006 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
1007 let v2 = &[10, 11, 12];
1010 assert_eq!((0..).size_hint(), (usize::MAX, None));
1011 assert_eq!(c.size_hint(), (usize::MAX, None));
1012 assert_eq!(vi.clone().size_hint(), (10, Some(10)));
1014 assert_eq!(c.clone().take(5).size_hint(), (5, Some(5)));
1015 assert_eq!(c.clone().skip(5).size_hint().1, None);
1016 assert_eq!(c.clone().take_while(|_| false).size_hint(), (0, None));
1017 assert_eq!(c.clone().skip_while(|_| false).size_hint(), (0, None));
1018 assert_eq!(c.clone().enumerate().size_hint(), (usize::MAX, None));
1019 assert_eq!(c.clone().chain(vi.clone().cloned()).size_hint(), (usize::MAX, None));
1020 assert_eq!(c.clone().zip(vi.clone()).size_hint(), (10, Some(10)));
1021 assert_eq!(c.clone().scan(0, |_,_| Some(0)).size_hint(), (0, None));
1022 assert_eq!(c.clone().filter(|_| false).size_hint(), (0, None));
1023 assert_eq!(c.clone().map(|_| 0).size_hint(), (usize::MAX, None));
1024 assert_eq!(c.filter_map(|_| Some(0)).size_hint(), (0, None));
1026 assert_eq!(vi.clone().take(5).size_hint(), (5, Some(5)));
1027 assert_eq!(vi.clone().take(12).size_hint(), (10, Some(10)));
1028 assert_eq!(vi.clone().skip(3).size_hint(), (7, Some(7)));
1029 assert_eq!(vi.clone().skip(12).size_hint(), (0, Some(0)));
1030 assert_eq!(vi.clone().take_while(|_| false).size_hint(), (0, Some(10)));
1031 assert_eq!(vi.clone().skip_while(|_| false).size_hint(), (0, Some(10)));
1032 assert_eq!(vi.clone().enumerate().size_hint(), (10, Some(10)));
1033 assert_eq!(vi.clone().chain(v2).size_hint(), (13, Some(13)));
1034 assert_eq!(vi.clone().zip(v2).size_hint(), (3, Some(3)));
1035 assert_eq!(vi.clone().scan(0, |_,_| Some(0)).size_hint(), (0, Some(10)));
1036 assert_eq!(vi.clone().filter(|_| false).size_hint(), (0, Some(10)));
1037 assert_eq!(vi.clone().map(|&i| i+1).size_hint(), (10, Some(10)));
1038 assert_eq!(vi.filter_map(|_| Some(0)).size_hint(), (0, Some(10)));
1043 let a = vec![1, 2, 3, 4, 5];
1044 let b: Vec<isize> = a.iter().cloned().collect();
1050 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
1051 assert!(v.iter().all(|&x| x < 10));
1052 assert!(!v.iter().all(|&x| x % 2 == 0));
1053 assert!(!v.iter().all(|&x| x > 100));
1054 assert!(v[..0].iter().all(|_| panic!()));
1059 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
1060 assert!(v.iter().any(|&x| x < 10));
1061 assert!(v.iter().any(|&x| x % 2 == 0));
1062 assert!(!v.iter().any(|&x| x > 100));
1063 assert!(!v[..0].iter().any(|_| panic!()));
1068 let v: &[isize] = &[1, 3, 9, 27, 103, 14, 11];
1069 assert_eq!(*v.iter().find(|&&x| x & 1 == 0).unwrap(), 14);
1070 assert_eq!(*v.iter().find(|&&x| x % 3 == 0).unwrap(), 3);
1071 assert!(v.iter().find(|&&x| x % 12 == 0).is_none());
1075 fn test_position() {
1076 let v = &[1, 3, 9, 27, 103, 14, 11];
1077 assert_eq!(v.iter().position(|x| *x & 1 == 0).unwrap(), 5);
1078 assert_eq!(v.iter().position(|x| *x % 3 == 0).unwrap(), 1);
1079 assert!(v.iter().position(|x| *x % 12 == 0).is_none());
1084 let xs = &[1, 2, 2, 1, 5, 9, 0, 2];
1085 assert_eq!(xs.iter().filter(|x| **x == 2).count(), 3);
1086 assert_eq!(xs.iter().filter(|x| **x == 5).count(), 1);
1087 assert_eq!(xs.iter().filter(|x| **x == 95).count(), 0);
1091 fn test_max_by_key() {
1092 let xs: &[isize] = &[-3, 0, 1, 5, -10];
1093 assert_eq!(*xs.iter().max_by_key(|x| x.abs()).unwrap(), -10);
1098 let xs: &[isize] = &[-3, 0, 1, 5, -10];
1099 assert_eq!(*xs.iter().max_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), -10);
1103 fn test_min_by_key() {
1104 let xs: &[isize] = &[-3, 0, 1, 5, -10];
1105 assert_eq!(*xs.iter().min_by_key(|x| x.abs()).unwrap(), 0);
1110 let xs: &[isize] = &[-3, 0, 1, 5, -10];
1111 assert_eq!(*xs.iter().min_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), 0);
1117 // sum the first five values
1118 let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b);
1119 assert_eq!(partial_sum, 10);
1120 assert_eq!(xs.next(), Some(5));
1125 let xs = [2, 4, 6, 8, 10, 12, 14, 16];
1126 let mut it = xs.iter();
1129 assert!(it.rev().cloned().collect::<Vec<isize>>() ==
1130 vec![16, 14, 12, 10, 8, 6]);
1135 let xs = [2, 4, 6, 8];
1137 let mut it = xs.iter().cloned();
1138 assert_eq!(it.len(), 4);
1139 assert_eq!(it.next(), Some(2));
1140 assert_eq!(it.len(), 3);
1141 assert_eq!(it.next(), Some(4));
1142 assert_eq!(it.len(), 2);
1143 assert_eq!(it.next_back(), Some(8));
1144 assert_eq!(it.len(), 1);
1145 assert_eq!(it.next_back(), Some(6));
1146 assert_eq!(it.len(), 0);
1147 assert_eq!(it.next_back(), None);
1151 fn test_double_ended_map() {
1152 let xs = [1, 2, 3, 4, 5, 6];
1153 let mut it = xs.iter().map(|&x| x * -1);
1154 assert_eq!(it.next(), Some(-1));
1155 assert_eq!(it.next(), Some(-2));
1156 assert_eq!(it.next_back(), Some(-6));
1157 assert_eq!(it.next_back(), Some(-5));
1158 assert_eq!(it.next(), Some(-3));
1159 assert_eq!(it.next_back(), Some(-4));
1160 assert_eq!(it.next(), None);
1164 fn test_double_ended_enumerate() {
1165 let xs = [1, 2, 3, 4, 5, 6];
1166 let mut it = xs.iter().cloned().enumerate();
1167 assert_eq!(it.next(), Some((0, 1)));
1168 assert_eq!(it.next(), Some((1, 2)));
1169 assert_eq!(it.next_back(), Some((5, 6)));
1170 assert_eq!(it.next_back(), Some((4, 5)));
1171 assert_eq!(it.next_back(), Some((3, 4)));
1172 assert_eq!(it.next_back(), Some((2, 3)));
1173 assert_eq!(it.next(), None);
1177 fn test_double_ended_zip() {
1178 let xs = [1, 2, 3, 4, 5, 6];
1179 let ys = [1, 2, 3, 7];
1180 let a = xs.iter().cloned();
1181 let b = ys.iter().cloned();
1182 let mut it = a.zip(b);
1183 assert_eq!(it.next(), Some((1, 1)));
1184 assert_eq!(it.next(), Some((2, 2)));
1185 assert_eq!(it.next_back(), Some((4, 7)));
1186 assert_eq!(it.next_back(), Some((3, 3)));
1187 assert_eq!(it.next(), None);
1191 fn test_double_ended_filter() {
1192 let xs = [1, 2, 3, 4, 5, 6];
1193 let mut it = xs.iter().filter(|&x| *x & 1 == 0);
1194 assert_eq!(it.next_back().unwrap(), &6);
1195 assert_eq!(it.next_back().unwrap(), &4);
1196 assert_eq!(it.next().unwrap(), &2);
1197 assert_eq!(it.next_back(), None);
1201 fn test_double_ended_filter_map() {
1202 let xs = [1, 2, 3, 4, 5, 6];
1203 let mut it = xs.iter().filter_map(|&x| if x & 1 == 0 { Some(x * 2) } else { None });
1204 assert_eq!(it.next_back().unwrap(), 12);
1205 assert_eq!(it.next_back().unwrap(), 8);
1206 assert_eq!(it.next().unwrap(), 4);
1207 assert_eq!(it.next_back(), None);
1211 fn test_double_ended_chain() {
1212 let xs = [1, 2, 3, 4, 5];
1213 let ys = [7, 9, 11];
1214 let mut it = xs.iter().chain(&ys).rev();
1215 assert_eq!(it.next().unwrap(), &11);
1216 assert_eq!(it.next().unwrap(), &9);
1217 assert_eq!(it.next_back().unwrap(), &1);
1218 assert_eq!(it.next_back().unwrap(), &2);
1219 assert_eq!(it.next_back().unwrap(), &3);
1220 assert_eq!(it.next_back().unwrap(), &4);
1221 assert_eq!(it.next_back().unwrap(), &5);
1222 assert_eq!(it.next_back().unwrap(), &7);
1223 assert_eq!(it.next_back(), None);
1226 // test that .chain() is well behaved with an unfused iterator
1227 struct CrazyIterator(bool);
1228 impl CrazyIterator { fn new() -> CrazyIterator { CrazyIterator(false) } }
1229 impl Iterator for CrazyIterator {
1231 fn next(&mut self) -> Option<i32> {
1232 if self.0 { Some(99) } else { self.0 = true; None }
1236 impl DoubleEndedIterator for CrazyIterator {
1237 fn next_back(&mut self) -> Option<i32> {
1242 assert_eq!(CrazyIterator::new().chain(0..10).rev().last(), Some(0));
1243 assert!((0..10).chain(CrazyIterator::new()).rev().any(|i| i == 0));
1247 fn test_rposition() {
1248 fn f(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'b' }
1249 fn g(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'd' }
1250 let v = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')];
1252 assert_eq!(v.iter().rposition(f), Some(3));
1253 assert!(v.iter().rposition(g).is_none());
1258 fn test_rposition_panic() {
1259 let v: [(Box<_>, Box<_>); 4] =
1260 [(box 0, box 0), (box 0, box 0),
1261 (box 0, box 0), (box 0, box 0)];
1263 v.iter().rposition(|_elt| {
1274 fn test_double_ended_flat_map() {
1277 let mut it = u.iter().flat_map(|x| &v[*x..v.len()]);
1278 assert_eq!(it.next_back().unwrap(), &8);
1279 assert_eq!(it.next().unwrap(), &5);
1280 assert_eq!(it.next_back().unwrap(), &7);
1281 assert_eq!(it.next_back().unwrap(), &6);
1282 assert_eq!(it.next_back().unwrap(), &8);
1283 assert_eq!(it.next().unwrap(), &6);
1284 assert_eq!(it.next_back().unwrap(), &7);
1285 assert_eq!(it.next_back(), None);
1286 assert_eq!(it.next(), None);
1287 assert_eq!(it.next_back(), None);
1291 fn test_double_ended_range() {
1292 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
1293 for _ in (10..0).rev() {
1294 panic!("unreachable");
1297 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
1298 for _ in (10..0).rev() {
1299 panic!("unreachable");
1305 assert_eq!((0..5).collect::<Vec<_>>(), [0, 1, 2, 3, 4]);
1306 assert_eq!((-10..-1).collect::<Vec<_>>(), [-10, -9, -8, -7, -6, -5, -4, -3, -2]);
1307 assert_eq!((0..5).rev().collect::<Vec<_>>(), [4, 3, 2, 1, 0]);
1308 assert_eq!((200..-5).count(), 0);
1309 assert_eq!((200..-5).rev().count(), 0);
1310 assert_eq!((200..200).count(), 0);
1311 assert_eq!((200..200).rev().count(), 0);
1313 assert_eq!((0..100).size_hint(), (100, Some(100)));
1314 // this test is only meaningful when sizeof usize < sizeof u64
1315 assert_eq!((usize::MAX - 1..usize::MAX).size_hint(), (1, Some(1)));
1316 assert_eq!((-10..-1).size_hint(), (9, Some(9)));
1317 assert_eq!((-1..-10).size_hint(), (0, Some(0)));
1319 assert_eq!((-70..58).size_hint(), (128, Some(128)));
1320 assert_eq!((-128..127).size_hint(), (255, Some(255)));
1321 assert_eq!((-2..isize::MAX).size_hint(),
1322 (isize::MAX as usize + 2, Some(isize::MAX as usize + 2)));
1326 fn test_range_inclusive_exhaustion() {
1327 let mut r = 10..=10;
1328 assert_eq!(r.next(), Some(10));
1329 assert_eq!(r, 1..=0);
1331 let mut r = 10..=10;
1332 assert_eq!(r.next_back(), Some(10));
1333 assert_eq!(r, 1..=0);
1335 let mut r = 10..=12;
1336 assert_eq!(r.nth(2), Some(12));
1337 assert_eq!(r, 1..=0);
1339 let mut r = 10..=12;
1340 assert_eq!(r.nth(5), None);
1341 assert_eq!(r, 1..=0);
1346 fn test_range_nth() {
1347 assert_eq!((10..15).nth(0), Some(10));
1348 assert_eq!((10..15).nth(1), Some(11));
1349 assert_eq!((10..15).nth(4), Some(14));
1350 assert_eq!((10..15).nth(5), None);
1353 assert_eq!(r.nth(2), Some(12));
1354 assert_eq!(r, 13..20);
1355 assert_eq!(r.nth(2), Some(15));
1356 assert_eq!(r, 16..20);
1357 assert_eq!(r.nth(10), None);
1358 assert_eq!(r, 20..20);
1362 fn test_range_from_nth() {
1363 assert_eq!((10..).nth(0), Some(10));
1364 assert_eq!((10..).nth(1), Some(11));
1365 assert_eq!((10..).nth(4), Some(14));
1368 assert_eq!(r.nth(2), Some(12));
1369 assert_eq!(r, 13..);
1370 assert_eq!(r.nth(2), Some(15));
1371 assert_eq!(r, 16..);
1372 assert_eq!(r.nth(10), Some(26));
1373 assert_eq!(r, 27..);
1377 fn test_range_inclusive_nth() {
1378 assert_eq!((10..=15).nth(0), Some(10));
1379 assert_eq!((10..=15).nth(1), Some(11));
1380 assert_eq!((10..=15).nth(5), Some(15));
1381 assert_eq!((10..=15).nth(6), None);
1383 let mut r = 10_u8..=20;
1384 assert_eq!(r.nth(2), Some(12));
1385 assert_eq!(r, 13..=20);
1386 assert_eq!(r.nth(2), Some(15));
1387 assert_eq!(r, 16..=20);
1388 assert_eq!(r.is_empty(), false);
1389 assert_eq!(r.nth(10), None);
1390 assert_eq!(r.is_empty(), true);
1391 assert_eq!(r, 1..=0); // We may not want to document/promise this detail
1395 fn test_range_step() {
1396 #![allow(deprecated)]
1398 assert_eq!((0..20).step_by(5).collect::<Vec<isize>>(), [0, 5, 10, 15]);
1399 assert_eq!((1..21).rev().step_by(5).collect::<Vec<isize>>(), [20, 15, 10, 5]);
1400 assert_eq!((1..21).rev().step_by(6).collect::<Vec<isize>>(), [20, 14, 8, 2]);
1401 assert_eq!((200..255).step_by(50).collect::<Vec<u8>>(), [200, 250]);
1402 assert_eq!((200..-5).step_by(1).collect::<Vec<isize>>(), []);
1403 assert_eq!((200..200).step_by(1).collect::<Vec<isize>>(), []);
1405 assert_eq!((0..20).step_by(1).size_hint(), (20, Some(20)));
1406 assert_eq!((0..20).step_by(21).size_hint(), (1, Some(1)));
1407 assert_eq!((0..20).step_by(5).size_hint(), (4, Some(4)));
1408 assert_eq!((1..21).rev().step_by(5).size_hint(), (4, Some(4)));
1409 assert_eq!((1..21).rev().step_by(6).size_hint(), (4, Some(4)));
1410 assert_eq!((20..-5).step_by(1).size_hint(), (0, Some(0)));
1411 assert_eq!((20..20).step_by(1).size_hint(), (0, Some(0)));
1412 assert_eq!((i8::MIN..i8::MAX).step_by(-(i8::MIN as i32) as usize).size_hint(), (2, Some(2)));
1413 assert_eq!((i16::MIN..i16::MAX).step_by(i16::MAX as usize).size_hint(), (3, Some(3)));
1414 assert_eq!((isize::MIN..isize::MAX).step_by(1).size_hint(), (usize::MAX, Some(usize::MAX)));
1418 fn test_range_last_max() {
1419 assert_eq!((0..20).last(), Some(19));
1420 assert_eq!((-20..0).last(), Some(-1));
1421 assert_eq!((5..5).last(), None);
1423 assert_eq!((0..20).max(), Some(19));
1424 assert_eq!((-20..0).max(), Some(-1));
1425 assert_eq!((5..5).max(), None);
1429 fn test_range_inclusive_last_max() {
1430 assert_eq!((0..=20).last(), Some(20));
1431 assert_eq!((-20..=0).last(), Some(0));
1432 assert_eq!((5..=5).last(), Some(5));
1433 let mut r = 10..=10;
1435 assert_eq!(r.last(), None);
1437 assert_eq!((0..=20).max(), Some(20));
1438 assert_eq!((-20..=0).max(), Some(0));
1439 assert_eq!((5..=5).max(), Some(5));
1440 let mut r = 10..=10;
1442 assert_eq!(r.max(), None);
1446 fn test_range_min() {
1447 assert_eq!((0..20).min(), Some(0));
1448 assert_eq!((-20..0).min(), Some(-20));
1449 assert_eq!((5..5).min(), None);
1453 fn test_range_inclusive_min() {
1454 assert_eq!((0..=20).min(), Some(0));
1455 assert_eq!((-20..=0).min(), Some(-20));
1456 assert_eq!((5..=5).min(), Some(5));
1457 let mut r = 10..=10;
1459 assert_eq!(r.min(), None);
1464 let mut it = repeat(42);
1465 assert_eq!(it.next(), Some(42));
1466 assert_eq!(it.next(), Some(42));
1467 assert_eq!(it.next(), Some(42));
1473 assert_eq!(it.len(), 3);
1474 assert_eq!(it.next(), Some(0));
1475 assert_eq!(it.len(), 2);
1476 assert_eq!(it.next(), Some(1));
1477 assert_eq!(it.len(), 1);
1478 assert_eq!(it.next(), Some(2));
1479 assert_eq!(it.len(), 0);
1480 assert_eq!(it.next(), None);
1481 assert_eq!(it.len(), 0);
1482 assert_eq!(it.next(), None);
1483 assert_eq!(it.len(), 0);
1484 assert_eq!(it.next(), None);
1485 assert_eq!(it.len(), 0);
1489 fn test_fuse_nth() {
1491 let mut it = xs.iter();
1493 assert_eq!(it.len(), 3);
1494 assert_eq!(it.nth(2), Some(&2));
1495 assert_eq!(it.len(), 0);
1496 assert_eq!(it.nth(2), None);
1497 assert_eq!(it.len(), 0);
1501 fn test_fuse_last() {
1505 assert_eq!(it.len(), 3);
1506 assert_eq!(it.last(), Some(&2));
1510 fn test_fuse_count() {
1514 assert_eq!(it.len(), 3);
1515 assert_eq!(it.count(), 3);
1516 // Can't check len now because count consumes.
1520 fn test_fuse_fold() {
1522 let it = xs.iter(); // `FusedIterator`
1523 let i = it.fuse().fold(0, |i, &x| {
1524 assert_eq!(x, xs[i]);
1527 assert_eq!(i, xs.len());
1529 let it = xs.iter(); // `FusedIterator`
1530 let i = it.fuse().rfold(xs.len(), |i, &x| {
1531 assert_eq!(x, xs[i - 1]);
1536 let it = xs.iter().scan((), |_, &x| Some(x)); // `!FusedIterator`
1537 let i = it.fuse().fold(0, |i, x| {
1538 assert_eq!(x, xs[i]);
1541 assert_eq!(i, xs.len());
1546 let mut it = once(42);
1547 assert_eq!(it.next(), Some(42));
1548 assert_eq!(it.next(), None);
1553 let mut it = empty::<i32>();
1554 assert_eq!(it.next(), None);
1558 fn test_chain_fold() {
1562 let mut iter = xs.iter().chain(&ys);
1564 let mut result = Vec::new();
1565 iter.fold((), |(), &elt| result.push(elt));
1566 assert_eq!(&[2, 3, 1, 2, 0], &result[..]);
1570 fn test_step_replace_unsigned() {
1572 let y = x.replace_zero();
1577 let y = x.replace_one();
1583 fn test_step_replace_signed() {
1585 let y = x.replace_zero();
1590 let y = x.replace_one();
1596 fn test_step_replace_no_between() {
1598 let y = x.replace_zero();
1603 let y = x.replace_one();
1609 fn test_rev_try_folds() {
1610 let f = &|acc, x| i32::checked_add(2*acc, x);
1611 assert_eq!((1..10).rev().try_fold(7, f), (1..10).try_rfold(7, f));
1612 assert_eq!((1..10).rev().try_rfold(7, f), (1..10).try_fold(7, f));
1614 let a = [10, 20, 30, 40, 100, 60, 70, 80, 90];
1615 let mut iter = a.iter().rev();
1616 assert_eq!(iter.try_fold(0_i8, |acc, &x| acc.checked_add(x)), None);
1617 assert_eq!(iter.next(), Some(&70));
1618 let mut iter = a.iter().rev();
1619 assert_eq!(iter.try_rfold(0_i8, |acc, &x| acc.checked_add(x)), None);
1620 assert_eq!(iter.next_back(), Some(&60));
1624 fn test_cloned_try_folds() {
1625 let a = [1, 2, 3, 4, 5, 6, 7, 8, 9];
1626 let f = &|acc, x| i32::checked_add(2*acc, x);
1627 let f_ref = &|acc, &x| i32::checked_add(2*acc, x);
1628 assert_eq!(a.iter().cloned().try_fold(7, f), a.iter().try_fold(7, f_ref));
1629 assert_eq!(a.iter().cloned().try_rfold(7, f), a.iter().try_rfold(7, f_ref));
1631 let a = [10, 20, 30, 40, 100, 60, 70, 80, 90];
1632 let mut iter = a.iter().cloned();
1633 assert_eq!(iter.try_fold(0_i8, |acc, x| acc.checked_add(x)), None);
1634 assert_eq!(iter.next(), Some(60));
1635 let mut iter = a.iter().cloned();
1636 assert_eq!(iter.try_rfold(0_i8, |acc, x| acc.checked_add(x)), None);
1637 assert_eq!(iter.next_back(), Some(70));
1641 fn test_chain_try_folds() {
1642 let c = || (0..10).chain(10..20);
1644 let f = &|acc, x| i32::checked_add(2*acc, x);
1645 assert_eq!(c().try_fold(7, f), (0..20).try_fold(7, f));
1646 assert_eq!(c().try_rfold(7, f), (0..20).rev().try_fold(7, f));
1649 assert_eq!(iter.position(|x| x == 5), Some(5));
1650 assert_eq!(iter.next(), Some(6), "stopped in front, state Both");
1651 assert_eq!(iter.position(|x| x == 13), Some(6));
1652 assert_eq!(iter.next(), Some(14), "stopped in back, state Back");
1653 assert_eq!(iter.try_fold(0, |acc, x| Some(acc+x)), Some((15..20).sum()));
1655 let mut iter = c().rev(); // use rev to access try_rfold
1656 assert_eq!(iter.position(|x| x == 15), Some(4));
1657 assert_eq!(iter.next(), Some(14), "stopped in back, state Both");
1658 assert_eq!(iter.position(|x| x == 5), Some(8));
1659 assert_eq!(iter.next(), Some(4), "stopped in front, state Front");
1660 assert_eq!(iter.try_fold(0, |acc, x| Some(acc+x)), Some((0..4).sum()));
1663 iter.by_ref().rev().nth(14); // skip the last 15, ending in state Front
1664 assert_eq!(iter.try_fold(7, f), (0..5).try_fold(7, f));
1667 iter.nth(14); // skip the first 15, ending in state Back
1668 assert_eq!(iter.try_rfold(7, f), (15..20).try_rfold(7, f));
1672 fn test_map_try_folds() {
1673 let f = &|acc, x| i32::checked_add(2*acc, x);
1674 assert_eq!((0..10).map(|x| x+3).try_fold(7, f), (3..13).try_fold(7, f));
1675 assert_eq!((0..10).map(|x| x+3).try_rfold(7, f), (3..13).try_rfold(7, f));
1677 let mut iter = (0..40).map(|x| x+10);
1678 assert_eq!(iter.try_fold(0, i8::checked_add), None);
1679 assert_eq!(iter.next(), Some(20));
1680 assert_eq!(iter.try_rfold(0, i8::checked_add), None);
1681 assert_eq!(iter.next_back(), Some(46));
1685 fn test_filter_try_folds() {
1686 fn p(&x: &i32) -> bool { 0 <= x && x < 10 }
1687 let f = &|acc, x| i32::checked_add(2*acc, x);
1688 assert_eq!((-10..20).filter(p).try_fold(7, f), (0..10).try_fold(7, f));
1689 assert_eq!((-10..20).filter(p).try_rfold(7, f), (0..10).try_rfold(7, f));
1691 let mut iter = (0..40).filter(|&x| x % 2 == 1);
1692 assert_eq!(iter.try_fold(0, i8::checked_add), None);
1693 assert_eq!(iter.next(), Some(25));
1694 assert_eq!(iter.try_rfold(0, i8::checked_add), None);
1695 assert_eq!(iter.next_back(), Some(31));
1699 fn test_filter_map_try_folds() {
1700 let mp = &|x| if 0 <= x && x < 10 { Some(x*2) } else { None };
1701 let f = &|acc, x| i32::checked_add(2*acc, x);
1702 assert_eq!((-9..20).filter_map(mp).try_fold(7, f), (0..10).map(|x| 2*x).try_fold(7, f));
1703 assert_eq!((-9..20).filter_map(mp).try_rfold(7, f), (0..10).map(|x| 2*x).try_rfold(7, f));
1705 let mut iter = (0..40).filter_map(|x| if x%2 == 1 { None } else { Some(x*2 + 10) });
1706 assert_eq!(iter.try_fold(0, i8::checked_add), None);
1707 assert_eq!(iter.next(), Some(38));
1708 assert_eq!(iter.try_rfold(0, i8::checked_add), None);
1709 assert_eq!(iter.next_back(), Some(78));
1713 fn test_enumerate_try_folds() {
1714 let f = &|acc, (i, x)| usize::checked_add(2*acc, x/(i+1) + i);
1715 assert_eq!((9..18).enumerate().try_fold(7, f), (0..9).map(|i| (i, i+9)).try_fold(7, f));
1716 assert_eq!((9..18).enumerate().try_rfold(7, f), (0..9).map(|i| (i, i+9)).try_rfold(7, f));
1718 let mut iter = (100..200).enumerate();
1719 let f = &|acc, (i, x)| u8::checked_add(acc, u8::checked_div(x, i as u8 + 1)?);
1720 assert_eq!(iter.try_fold(0, f), None);
1721 assert_eq!(iter.next(), Some((7, 107)));
1722 assert_eq!(iter.try_rfold(0, f), None);
1723 assert_eq!(iter.next_back(), Some((11, 111)));
1727 fn test_peek_try_fold() {
1728 let f = &|acc, x| i32::checked_add(2*acc, x);
1729 assert_eq!((1..20).peekable().try_fold(7, f), (1..20).try_fold(7, f));
1730 let mut iter = (1..20).peekable();
1731 assert_eq!(iter.peek(), Some(&1));
1732 assert_eq!(iter.try_fold(7, f), (1..20).try_fold(7, f));
1734 let mut iter = [100, 20, 30, 40, 50, 60, 70].iter().cloned().peekable();
1735 assert_eq!(iter.peek(), Some(&100));
1736 assert_eq!(iter.try_fold(0, i8::checked_add), None);
1737 assert_eq!(iter.peek(), Some(&40));
1741 fn test_skip_while_try_fold() {
1742 let f = &|acc, x| i32::checked_add(2*acc, x);
1743 fn p(&x: &i32) -> bool { (x % 10) <= 5 }
1744 assert_eq!((1..20).skip_while(p).try_fold(7, f), (6..20).try_fold(7, f));
1745 let mut iter = (1..20).skip_while(p);
1746 assert_eq!(iter.nth(5), Some(11));
1747 assert_eq!(iter.try_fold(7, f), (12..20).try_fold(7, f));
1749 let mut iter = (0..50).skip_while(|&x| (x % 20) < 15);
1750 assert_eq!(iter.try_fold(0, i8::checked_add), None);
1751 assert_eq!(iter.next(), Some(23));
1755 fn test_take_while_folds() {
1756 let f = &|acc, x| i32::checked_add(2*acc, x);
1757 assert_eq!((1..20).take_while(|&x| x != 10).try_fold(7, f), (1..10).try_fold(7, f));
1758 let mut iter = (1..20).take_while(|&x| x != 10);
1759 assert_eq!(iter.try_fold(0, |x, y| Some(x+y)), Some((1..10).sum()));
1760 assert_eq!(iter.next(), None, "flag should be set");
1761 let iter = (1..20).take_while(|&x| x != 10);
1762 assert_eq!(iter.fold(0, |x, y| x+y), (1..10).sum());
1764 let mut iter = (10..50).take_while(|&x| x != 40);
1765 assert_eq!(iter.try_fold(0, i8::checked_add), None);
1766 assert_eq!(iter.next(), Some(20));
1770 fn test_skip_try_folds() {
1771 let f = &|acc, x| i32::checked_add(2*acc, x);
1772 assert_eq!((1..20).skip(9).try_fold(7, f), (10..20).try_fold(7, f));
1773 assert_eq!((1..20).skip(9).try_rfold(7, f), (10..20).try_rfold(7, f));
1775 let mut iter = (0..30).skip(10);
1776 assert_eq!(iter.try_fold(0, i8::checked_add), None);
1777 assert_eq!(iter.next(), Some(20));
1778 assert_eq!(iter.try_rfold(0, i8::checked_add), None);
1779 assert_eq!(iter.next_back(), Some(24));
1783 fn test_take_try_folds() {
1784 let f = &|acc, x| i32::checked_add(2*acc, x);
1785 assert_eq!((10..30).take(10).try_fold(7, f), (10..20).try_fold(7, f));
1786 //assert_eq!((10..30).take(10).try_rfold(7, f), (10..20).try_rfold(7, f));
1788 let mut iter = (10..30).take(20);
1789 assert_eq!(iter.try_fold(0, i8::checked_add), None);
1790 assert_eq!(iter.next(), Some(20));
1791 //assert_eq!(iter.try_rfold(0, i8::checked_add), None);
1792 //assert_eq!(iter.next_back(), Some(24));
1796 fn test_flat_map_try_folds() {
1797 let f = &|acc, x| i32::checked_add(acc*2/3, x);
1798 let mr = &|x| (5*x)..(5*x + 5);
1799 assert_eq!((0..10).flat_map(mr).try_fold(7, f), (0..50).try_fold(7, f));
1800 assert_eq!((0..10).flat_map(mr).try_rfold(7, f), (0..50).try_rfold(7, f));
1801 let mut iter = (0..10).flat_map(mr);
1802 iter.next(); iter.next_back(); // have front and back iters in progress
1803 assert_eq!(iter.try_rfold(7, f), (1..49).try_rfold(7, f));
1805 let mut iter = (0..10).flat_map(|x| (4*x)..(4*x + 4));
1806 assert_eq!(iter.try_fold(0, i8::checked_add), None);
1807 assert_eq!(iter.next(), Some(17));
1808 assert_eq!(iter.try_rfold(0, i8::checked_add), None);
1809 assert_eq!(iter.next_back(), Some(35));