eef4d42a3f
This is the core method in terms of which the other methods (fold, all, any, find, position, nth, ...) can be implemented, allowing Iterator implementors to get the full goodness of internal iteration by only overriding one method (per direction).
1703 lines
49 KiB
Rust
1703 lines
49 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use core::iter::*;
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use core::{i8, i16, isize};
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use core::usize;
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#[test]
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fn test_lt() {
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let empty: [isize; 0] = [];
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let xs = [1,2,3];
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let ys = [1,2,0];
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assert!(!xs.iter().lt(ys.iter()));
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assert!(!xs.iter().le(ys.iter()));
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assert!( xs.iter().gt(ys.iter()));
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assert!( xs.iter().ge(ys.iter()));
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assert!( ys.iter().lt(xs.iter()));
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assert!( ys.iter().le(xs.iter()));
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assert!(!ys.iter().gt(xs.iter()));
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assert!(!ys.iter().ge(xs.iter()));
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assert!( empty.iter().lt(xs.iter()));
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assert!( empty.iter().le(xs.iter()));
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assert!(!empty.iter().gt(xs.iter()));
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assert!(!empty.iter().ge(xs.iter()));
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// Sequence with NaN
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let u = [1.0f64, 2.0];
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let v = [0.0f64/0.0, 3.0];
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assert!(!u.iter().lt(v.iter()));
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assert!(!u.iter().le(v.iter()));
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assert!(!u.iter().gt(v.iter()));
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assert!(!u.iter().ge(v.iter()));
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let a = [0.0f64/0.0];
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let b = [1.0f64];
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let c = [2.0f64];
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assert!(a.iter().lt(b.iter()) == (a[0] < b[0]));
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assert!(a.iter().le(b.iter()) == (a[0] <= b[0]));
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assert!(a.iter().gt(b.iter()) == (a[0] > b[0]));
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assert!(a.iter().ge(b.iter()) == (a[0] >= b[0]));
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assert!(c.iter().lt(b.iter()) == (c[0] < b[0]));
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assert!(c.iter().le(b.iter()) == (c[0] <= b[0]));
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assert!(c.iter().gt(b.iter()) == (c[0] > b[0]));
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assert!(c.iter().ge(b.iter()) == (c[0] >= b[0]));
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}
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#[test]
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fn test_multi_iter() {
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let xs = [1,2,3,4];
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let ys = [4,3,2,1];
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assert!(xs.iter().eq(ys.iter().rev()));
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assert!(xs.iter().lt(xs.iter().skip(2)));
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}
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#[test]
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fn test_counter_from_iter() {
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let it = (0..).step_by(5).take(10);
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let xs: Vec<isize> = FromIterator::from_iter(it);
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assert_eq!(xs, [0, 5, 10, 15, 20, 25, 30, 35, 40, 45]);
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}
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#[test]
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fn test_iterator_chain() {
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let xs = [0, 1, 2, 3, 4, 5];
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let ys = [30, 40, 50, 60];
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let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
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let it = xs.iter().chain(&ys);
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let mut i = 0;
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for &x in it {
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assert_eq!(x, expected[i]);
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i += 1;
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}
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assert_eq!(i, expected.len());
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let ys = (30..).step_by(10).take(4);
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let it = xs.iter().cloned().chain(ys);
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let mut i = 0;
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for x in it {
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assert_eq!(x, expected[i]);
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i += 1;
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}
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assert_eq!(i, expected.len());
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}
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#[test]
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fn test_iterator_chain_nth() {
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let xs = [0, 1, 2, 3, 4, 5];
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let ys = [30, 40, 50, 60];
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let zs = [];
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let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
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for (i, x) in expected.iter().enumerate() {
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assert_eq!(Some(x), xs.iter().chain(&ys).nth(i));
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}
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assert_eq!(zs.iter().chain(&xs).nth(0), Some(&0));
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let mut it = xs.iter().chain(&zs);
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assert_eq!(it.nth(5), Some(&5));
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assert_eq!(it.next(), None);
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}
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#[test]
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fn test_iterator_chain_last() {
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let xs = [0, 1, 2, 3, 4, 5];
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let ys = [30, 40, 50, 60];
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let zs = [];
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assert_eq!(xs.iter().chain(&ys).last(), Some(&60));
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assert_eq!(zs.iter().chain(&ys).last(), Some(&60));
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assert_eq!(ys.iter().chain(&zs).last(), Some(&60));
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assert_eq!(zs.iter().chain(&zs).last(), None);
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}
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#[test]
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fn test_iterator_chain_count() {
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let xs = [0, 1, 2, 3, 4, 5];
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let ys = [30, 40, 50, 60];
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let zs = [];
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assert_eq!(xs.iter().chain(&ys).count(), 10);
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assert_eq!(zs.iter().chain(&ys).count(), 4);
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}
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#[test]
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fn test_iterator_chain_find() {
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let xs = [0, 1, 2, 3, 4, 5];
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let ys = [30, 40, 50, 60];
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let mut iter = xs.iter().chain(&ys);
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assert_eq!(iter.find(|&&i| i == 4), Some(&4));
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assert_eq!(iter.next(), Some(&5));
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assert_eq!(iter.find(|&&i| i == 40), Some(&40));
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assert_eq!(iter.next(), Some(&50));
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assert_eq!(iter.find(|&&i| i == 100), None);
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assert_eq!(iter.next(), None);
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}
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#[test]
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fn test_iterator_step_by() {
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// Identity
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let mut it = (0..).step_by(1).take(3);
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assert_eq!(it.next(), Some(0));
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assert_eq!(it.next(), Some(1));
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assert_eq!(it.next(), Some(2));
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assert_eq!(it.next(), None);
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let mut it = (0..).step_by(3).take(4);
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assert_eq!(it.next(), Some(0));
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assert_eq!(it.next(), Some(3));
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assert_eq!(it.next(), Some(6));
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assert_eq!(it.next(), Some(9));
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assert_eq!(it.next(), None);
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}
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#[test]
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#[should_panic]
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fn test_iterator_step_by_zero() {
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let mut it = (0..).step_by(0);
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it.next();
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}
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#[test]
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fn test_iterator_step_by_size_hint() {
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struct StubSizeHint(usize, Option<usize>);
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impl Iterator for StubSizeHint {
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type Item = ();
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fn next(&mut self) -> Option<()> {
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self.0 -= 1;
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if let Some(ref mut upper) = self.1 {
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*upper -= 1;
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}
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Some(())
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}
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fn size_hint(&self) -> (usize, Option<usize>) {
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(self.0, self.1)
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}
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}
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// The two checks in each case are needed because the logic
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// is different before the first call to `next()`.
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let mut it = StubSizeHint(10, Some(10)).step_by(1);
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assert_eq!(it.size_hint(), (10, Some(10)));
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it.next();
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assert_eq!(it.size_hint(), (9, Some(9)));
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// exact multiple
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let mut it = StubSizeHint(10, Some(10)).step_by(3);
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assert_eq!(it.size_hint(), (4, Some(4)));
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it.next();
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assert_eq!(it.size_hint(), (3, Some(3)));
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// larger base range, but not enough to get another element
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let mut it = StubSizeHint(12, Some(12)).step_by(3);
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assert_eq!(it.size_hint(), (4, Some(4)));
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it.next();
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assert_eq!(it.size_hint(), (3, Some(3)));
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// smaller base range, so fewer resulting elements
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let mut it = StubSizeHint(9, Some(9)).step_by(3);
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assert_eq!(it.size_hint(), (3, Some(3)));
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it.next();
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assert_eq!(it.size_hint(), (2, Some(2)));
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// infinite upper bound
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let mut it = StubSizeHint(usize::MAX, None).step_by(1);
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assert_eq!(it.size_hint(), (usize::MAX, None));
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it.next();
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assert_eq!(it.size_hint(), (usize::MAX-1, None));
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// still infinite with larger step
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let mut it = StubSizeHint(7, None).step_by(3);
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assert_eq!(it.size_hint(), (3, None));
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it.next();
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assert_eq!(it.size_hint(), (2, None));
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// propagates ExactSizeIterator
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let a = [1,2,3,4,5];
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let it = a.iter().step_by(2);
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assert_eq!(it.len(), 3);
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// Cannot be TrustedLen as a step greater than one makes an iterator
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// with (usize::MAX, None) no longer meet the safety requirements
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trait TrustedLenCheck { fn test(self) -> bool; }
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impl<T:Iterator> TrustedLenCheck for T {
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default fn test(self) -> bool { false }
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}
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impl<T:TrustedLen> TrustedLenCheck for T {
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fn test(self) -> bool { true }
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}
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assert!(TrustedLenCheck::test(a.iter()));
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assert!(!TrustedLenCheck::test(a.iter().step_by(1)));
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}
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#[test]
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fn test_filter_map() {
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let it = (0..).step_by(1).take(10)
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.filter_map(|x| if x % 2 == 0 { Some(x*x) } else { None });
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assert_eq!(it.collect::<Vec<usize>>(), [0*0, 2*2, 4*4, 6*6, 8*8]);
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}
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#[test]
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fn test_filter_map_fold() {
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let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8];
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let ys = [0*0, 2*2, 4*4, 6*6, 8*8];
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let it = xs.iter().filter_map(|&x| if x % 2 == 0 { Some(x*x) } else { None });
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let i = it.fold(0, |i, x| {
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assert_eq!(x, ys[i]);
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i + 1
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});
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assert_eq!(i, ys.len());
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let it = xs.iter().filter_map(|&x| if x % 2 == 0 { Some(x*x) } else { None });
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let i = it.rfold(ys.len(), |i, x| {
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assert_eq!(x, ys[i - 1]);
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i - 1
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});
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assert_eq!(i, 0);
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}
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#[test]
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fn test_iterator_enumerate() {
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let xs = [0, 1, 2, 3, 4, 5];
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let it = xs.iter().enumerate();
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for (i, &x) in it {
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assert_eq!(i, x);
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}
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}
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#[test]
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fn test_iterator_enumerate_nth() {
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let xs = [0, 1, 2, 3, 4, 5];
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for (i, &x) in xs.iter().enumerate() {
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assert_eq!(i, x);
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}
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let mut it = xs.iter().enumerate();
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while let Some((i, &x)) = it.nth(0) {
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assert_eq!(i, x);
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}
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let mut it = xs.iter().enumerate();
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while let Some((i, &x)) = it.nth(1) {
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assert_eq!(i, x);
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}
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let (i, &x) = xs.iter().enumerate().nth(3).unwrap();
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assert_eq!(i, x);
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assert_eq!(i, 3);
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}
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#[test]
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fn test_iterator_enumerate_count() {
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let xs = [0, 1, 2, 3, 4, 5];
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assert_eq!(xs.iter().enumerate().count(), 6);
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}
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#[test]
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fn test_iterator_enumerate_fold() {
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let xs = [0, 1, 2, 3, 4, 5];
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let mut it = xs.iter().enumerate();
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// steal a couple to get an interesting offset
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assert_eq!(it.next(), Some((0, &0)));
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assert_eq!(it.next(), Some((1, &1)));
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let i = it.fold(2, |i, (j, &x)| {
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assert_eq!(i, j);
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assert_eq!(x, xs[j]);
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i + 1
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});
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assert_eq!(i, xs.len());
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let mut it = xs.iter().enumerate();
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assert_eq!(it.next(), Some((0, &0)));
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let i = it.rfold(xs.len() - 1, |i, (j, &x)| {
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assert_eq!(i, j);
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assert_eq!(x, xs[j]);
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i - 1
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});
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assert_eq!(i, 0);
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}
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#[test]
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fn test_iterator_filter_count() {
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let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8];
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assert_eq!(xs.iter().filter(|&&x| x % 2 == 0).count(), 5);
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}
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#[test]
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fn test_iterator_filter_fold() {
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let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8];
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let ys = [0, 2, 4, 6, 8];
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let it = xs.iter().filter(|&&x| x % 2 == 0);
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let i = it.fold(0, |i, &x| {
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assert_eq!(x, ys[i]);
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i + 1
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});
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assert_eq!(i, ys.len());
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let it = xs.iter().filter(|&&x| x % 2 == 0);
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let i = it.rfold(ys.len(), |i, &x| {
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assert_eq!(x, ys[i - 1]);
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i - 1
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});
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assert_eq!(i, 0);
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}
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#[test]
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fn test_iterator_peekable() {
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let xs = vec![0, 1, 2, 3, 4, 5];
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let mut it = xs.iter().cloned().peekable();
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assert_eq!(it.len(), 6);
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assert_eq!(it.peek().unwrap(), &0);
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assert_eq!(it.len(), 6);
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assert_eq!(it.next().unwrap(), 0);
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assert_eq!(it.len(), 5);
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assert_eq!(it.next().unwrap(), 1);
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assert_eq!(it.len(), 4);
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assert_eq!(it.next().unwrap(), 2);
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assert_eq!(it.len(), 3);
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assert_eq!(it.peek().unwrap(), &3);
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assert_eq!(it.len(), 3);
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assert_eq!(it.peek().unwrap(), &3);
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assert_eq!(it.len(), 3);
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assert_eq!(it.next().unwrap(), 3);
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assert_eq!(it.len(), 2);
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assert_eq!(it.next().unwrap(), 4);
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assert_eq!(it.len(), 1);
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assert_eq!(it.peek().unwrap(), &5);
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assert_eq!(it.len(), 1);
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assert_eq!(it.next().unwrap(), 5);
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assert_eq!(it.len(), 0);
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assert!(it.peek().is_none());
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assert_eq!(it.len(), 0);
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assert!(it.next().is_none());
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assert_eq!(it.len(), 0);
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}
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#[test]
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fn test_iterator_peekable_count() {
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let xs = [0, 1, 2, 3, 4, 5];
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let ys = [10];
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let zs: [i32; 0] = [];
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assert_eq!(xs.iter().peekable().count(), 6);
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let mut it = xs.iter().peekable();
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assert_eq!(it.peek(), Some(&&0));
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assert_eq!(it.count(), 6);
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assert_eq!(ys.iter().peekable().count(), 1);
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let mut it = ys.iter().peekable();
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assert_eq!(it.peek(), Some(&&10));
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assert_eq!(it.count(), 1);
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assert_eq!(zs.iter().peekable().count(), 0);
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let mut it = zs.iter().peekable();
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assert_eq!(it.peek(), None);
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}
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#[test]
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fn test_iterator_peekable_nth() {
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let xs = [0, 1, 2, 3, 4, 5];
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let mut it = xs.iter().peekable();
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assert_eq!(it.peek(), Some(&&0));
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assert_eq!(it.nth(0), Some(&0));
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assert_eq!(it.peek(), Some(&&1));
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assert_eq!(it.nth(1), Some(&2));
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assert_eq!(it.peek(), Some(&&3));
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assert_eq!(it.nth(2), Some(&5));
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assert_eq!(it.next(), None);
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}
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#[test]
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fn test_iterator_peekable_last() {
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let xs = [0, 1, 2, 3, 4, 5];
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let ys = [0];
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let mut it = xs.iter().peekable();
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assert_eq!(it.peek(), Some(&&0));
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assert_eq!(it.last(), Some(&5));
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let mut it = ys.iter().peekable();
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assert_eq!(it.peek(), Some(&&0));
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assert_eq!(it.last(), Some(&0));
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let mut it = ys.iter().peekable();
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assert_eq!(it.next(), Some(&0));
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assert_eq!(it.peek(), None);
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assert_eq!(it.last(), None);
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}
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#[test]
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fn test_iterator_peekable_fold() {
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let xs = [0, 1, 2, 3, 4, 5];
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let mut it = xs.iter().peekable();
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assert_eq!(it.peek(), Some(&&0));
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let i = it.fold(0, |i, &x| {
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assert_eq!(x, xs[i]);
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i + 1
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});
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assert_eq!(i, xs.len());
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}
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/// This is an iterator that follows the Iterator contract,
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/// but it is not fused. After having returned None once, it will start
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/// producing elements if .next() is called again.
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pub struct CycleIter<'a, T: 'a> {
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index: usize,
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data: &'a [T],
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}
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pub fn cycle<T>(data: &[T]) -> CycleIter<T> {
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CycleIter {
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index: 0,
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data,
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}
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}
|
|
|
|
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(5);
|
|
let mut i = 0;
|
|
assert_eq!(it.len(), 5);
|
|
while let Some(&x) = it.next() {
|
|
assert_eq!(x, ys[i]);
|
|
i += 1;
|
|
assert_eq!(it.len(), 5-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_short() {
|
|
let xs = [0, 1, 2, 3];
|
|
let ys = [0, 1, 2, 3];
|
|
let mut it = xs.iter().take(5);
|
|
let mut i = 0;
|
|
assert_eq!(it.len(), 4);
|
|
while let Some(&x) = it.next() {
|
|
assert_eq!(x, ys[i]);
|
|
i += 1;
|
|
assert_eq!(it.len(), 4-i);
|
|
}
|
|
assert_eq!(i, ys.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());
|
|
}
|
|
|
|
/// Test `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_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);
|
|
}
|
|
|
|
#[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_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(()));
|
|
}
|
|
|
|
#[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(()));
|
|
}
|
|
|
|
#[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);
|
|
}
|
|
|
|
#[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);
|
|
}
|
|
|
|
#[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_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_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_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]
|
|
#[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_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_inclusive_exhaustion() {
|
|
let mut r = 10..=10;
|
|
assert_eq!(r.next(), Some(10));
|
|
assert_eq!(r, 1..=0);
|
|
|
|
let mut r = 10..=10;
|
|
assert_eq!(r.next_back(), Some(10));
|
|
assert_eq!(r, 1..=0);
|
|
|
|
let mut r = 10..=12;
|
|
assert_eq!(r.nth(2), Some(12));
|
|
assert_eq!(r, 1..=0);
|
|
|
|
let mut r = 10..=12;
|
|
assert_eq!(r.nth(5), None);
|
|
assert_eq!(r, 1..=0);
|
|
|
|
}
|
|
|
|
#[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_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..);
|
|
}
|
|
|
|
#[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!(r.nth(10), None);
|
|
assert_eq!(r.is_empty(), true);
|
|
assert_eq!(r, 1..=0); // We may not want to document/promise this detail
|
|
}
|
|
|
|
#[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_repeat() {
|
|
let mut it = repeat(42);
|
|
assert_eq!(it.next(), Some(42));
|
|
assert_eq!(it.next(), Some(42));
|
|
assert_eq!(it.next(), Some(42));
|
|
}
|
|
|
|
#[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_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_fold() {
|
|
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));
|
|
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 = [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));
|
|
}
|
|
|
|
#[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_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));
|
|
}
|
|
|
|
#[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));
|
|
}
|