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+//! The purpose of these tests is to cover corner cases of iterators
+//! and adaptors.
+//!
+//! In particular we test the tedious size_hint and exact size correctness.
+
+use quickcheck as qc;
+use std::default::Default;
+use std::num::Wrapping;
+use std::ops::Range;
+use std::cmp::{max, min, Ordering};
+use std::collections::{HashMap, HashSet};
+use itertools::Itertools;
+use itertools::{
+ multizip,
+ EitherOrBoth,
+ iproduct,
+ izip,
+};
+use itertools::free::{
+ cloned,
+ enumerate,
+ multipeek,
+ peek_nth,
+ put_back,
+ put_back_n,
+ rciter,
+ zip,
+ zip_eq,
+};
+
+use rand::Rng;
+use rand::seq::SliceRandom;
+use quickcheck::TestResult;
+
+/// Trait for size hint modifier types
+trait HintKind: Copy + Send + qc::Arbitrary {
+ fn loosen_bounds(&self, org_hint: (usize, Option<usize>)) -> (usize, Option<usize>);
+}
+
+/// Exact size hint variant that leaves hints unchanged
+#[derive(Clone, Copy, Debug)]
+struct Exact {}
+
+impl HintKind for Exact {
+ fn loosen_bounds(&self, org_hint: (usize, Option<usize>)) -> (usize, Option<usize>) {
+ org_hint
+ }
+}
+
+impl qc::Arbitrary for Exact {
+ fn arbitrary<G: qc::Gen>(_: &mut G) -> Self {
+ Exact {}
+ }
+}
+
+/// Inexact size hint variant to simulate imprecise (but valid) size hints
+///
+/// Will always decrease the lower bound and increase the upper bound
+/// of the size hint by set amounts.
+#[derive(Clone, Copy, Debug)]
+struct Inexact {
+ underestimate: usize,
+ overestimate: usize,
+}
+
+impl HintKind for Inexact {
+ fn loosen_bounds(&self, org_hint: (usize, Option<usize>)) -> (usize, Option<usize>) {
+ let (org_lower, org_upper) = org_hint;
+ (org_lower.saturating_sub(self.underestimate),
+ org_upper.and_then(move |x| x.checked_add(self.overestimate)))
+ }
+}
+
+impl qc::Arbitrary for Inexact {
+ fn arbitrary<G: qc::Gen>(g: &mut G) -> Self {
+ let ue_value = usize::arbitrary(g);
+ let oe_value = usize::arbitrary(g);
+ // Compensate for quickcheck using extreme values too rarely
+ let ue_choices = &[0, ue_value, usize::max_value()];
+ let oe_choices = &[0, oe_value, usize::max_value()];
+ Inexact {
+ underestimate: *ue_choices.choose(g).unwrap(),
+ overestimate: *oe_choices.choose(g).unwrap(),
+ }
+ }
+
+ fn shrink(&self) -> Box<dyn Iterator<Item=Self>> {
+ let underestimate_value = self.underestimate;
+ let overestimate_value = self.overestimate;
+ Box::new(
+ underestimate_value.shrink().flat_map(move |ue_value|
+ overestimate_value.shrink().map(move |oe_value|
+ Inexact {
+ underestimate: ue_value,
+ overestimate: oe_value,
+ }
+ )
+ )
+ )
+ }
+}
+
+/// Our base iterator that we can impl Arbitrary for
+///
+/// By default we'll return inexact bounds estimates for size_hint
+/// to make tests harder to pass.
+///
+/// NOTE: Iter is tricky and is not fused, to help catch bugs.
+/// At the end it will return None once, then return Some(0),
+/// then return None again.
+#[derive(Clone, Debug)]
+struct Iter<T, SK: HintKind = Inexact> {
+ iterator: Range<T>,
+ // fuse/done flag
+ fuse_flag: i32,
+ hint_kind: SK,
+}
+
+impl<T, HK> Iter<T, HK> where HK: HintKind
+{
+ fn new(it: Range<T>, hint_kind: HK) -> Self {
+ Iter {
+ iterator: it,
+ fuse_flag: 0,
+ hint_kind,
+ }
+ }
+}
+
+impl<T, HK> Iterator for Iter<T, HK>
+ where Range<T>: Iterator,
+ <Range<T> as Iterator>::Item: Default,
+ HK: HintKind,
+{
+ type Item = <Range<T> as Iterator>::Item;
+
+ fn next(&mut self) -> Option<Self::Item>
+ {
+ let elt = self.iterator.next();
+ if elt.is_none() {
+ self.fuse_flag += 1;
+ // check fuse flag
+ if self.fuse_flag == 2 {
+ return Some(Default::default())
+ }
+ }
+ elt
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>)
+ {
+ let org_hint = self.iterator.size_hint();
+ self.hint_kind.loosen_bounds(org_hint)
+ }
+}
+
+impl<T, HK> DoubleEndedIterator for Iter<T, HK>
+ where Range<T>: DoubleEndedIterator,
+ <Range<T> as Iterator>::Item: Default,
+ HK: HintKind
+{
+ fn next_back(&mut self) -> Option<Self::Item> { self.iterator.next_back() }
+}
+
+impl<T> ExactSizeIterator for Iter<T, Exact> where Range<T>: ExactSizeIterator,
+ <Range<T> as Iterator>::Item: Default,
+{ }
+
+impl<T, HK> qc::Arbitrary for Iter<T, HK>
+ where T: qc::Arbitrary,
+ HK: HintKind,
+{
+ fn arbitrary<G: qc::Gen>(g: &mut G) -> Self
+ {
+ Iter::new(T::arbitrary(g)..T::arbitrary(g), HK::arbitrary(g))
+ }
+
+ fn shrink(&self) -> Box<dyn Iterator<Item=Iter<T, HK>>>
+ {
+ let r = self.iterator.clone();
+ let hint_kind = self.hint_kind;
+ Box::new(
+ r.start.shrink().flat_map(move |a|
+ r.end.shrink().map(move |b|
+ Iter::new(a.clone()..b, hint_kind)
+ )
+ )
+ )
+ }
+}
+
+/// A meta-iterator which yields `Iter<i32>`s whose start/endpoints are
+/// increased or decreased linearly on each iteration.
+#[derive(Clone, Debug)]
+struct ShiftRange<HK = Inexact> {
+ range_start: i32,
+ range_end: i32,
+ start_step: i32,
+ end_step: i32,
+ iter_count: u32,
+ hint_kind: HK,
+}
+
+impl<HK> Iterator for ShiftRange<HK> where HK: HintKind {
+ type Item = Iter<i32, HK>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ if self.iter_count == 0 {
+ return None;
+ }
+
+ let iter = Iter::new(self.range_start..self.range_end, self.hint_kind);
+
+ self.range_start += self.start_step;
+ self.range_end += self.end_step;
+ self.iter_count -= 1;
+
+ Some(iter)
+ }
+}
+
+impl ExactSizeIterator for ShiftRange<Exact> { }
+
+impl<HK> qc::Arbitrary for ShiftRange<HK>
+ where HK: HintKind
+{
+ fn arbitrary<G: qc::Gen>(g: &mut G) -> Self {
+ const MAX_STARTING_RANGE_DIFF: i32 = 32;
+ const MAX_STEP_MODULO: i32 = 8;
+ const MAX_ITER_COUNT: u32 = 3;
+
+ let range_start = qc::Arbitrary::arbitrary(g);
+ let range_end = range_start + g.gen_range(0, MAX_STARTING_RANGE_DIFF + 1);
+ let start_step = g.gen_range(-MAX_STEP_MODULO, MAX_STEP_MODULO + 1);
+ let end_step = g.gen_range(-MAX_STEP_MODULO, MAX_STEP_MODULO + 1);
+ let iter_count = g.gen_range(0, MAX_ITER_COUNT + 1);
+ let hint_kind = qc::Arbitrary::arbitrary(g);
+
+ ShiftRange {
+ range_start,
+ range_end,
+ start_step,
+ end_step,
+ iter_count,
+ hint_kind,
+ }
+ }
+}
+
+fn correct_count<I, F>(get_it: F) -> bool
+where
+ I: Iterator,
+ F: Fn() -> I
+{
+ let mut counts = vec![get_it().count()];
+
+ 'outer: loop {
+ let mut it = get_it();
+
+ for _ in 0..(counts.len() - 1) {
+ if let None = it.next() {
+ panic!("Iterator shouldn't be finished, may not be deterministic");
+ }
+ }
+
+ if let None = it.next() {
+ break 'outer;
+ }
+
+ counts.push(it.count());
+ }
+
+ let total_actual_count = counts.len() - 1;
+
+ for (i, returned_count) in counts.into_iter().enumerate() {
+ let actual_count = total_actual_count - i;
+ if actual_count != returned_count {
+ println!("Total iterations: {} True count: {} returned count: {}", i, actual_count, returned_count);
+
+ return false;
+ }
+ }
+
+ true
+}
+
+fn correct_size_hint<I: Iterator>(mut it: I) -> bool {
+ // record size hint at each iteration
+ let initial_hint = it.size_hint();
+ let mut hints = Vec::with_capacity(initial_hint.0 + 1);
+ hints.push(initial_hint);
+ while let Some(_) = it.next() {
+ hints.push(it.size_hint())
+ }
+
+ let mut true_count = hints.len(); // start off +1 too much
+
+ // check all the size hints
+ for &(low, hi) in &hints {
+ true_count -= 1;
+ if low > true_count ||
+ (hi.is_some() && hi.unwrap() < true_count)
+ {
+ println!("True size: {:?}, size hint: {:?}", true_count, (low, hi));
+ //println!("All hints: {:?}", hints);
+ return false
+ }
+ }
+ true
+}
+
+fn exact_size<I: ExactSizeIterator>(mut it: I) -> bool {
+ // check every iteration
+ let (mut low, mut hi) = it.size_hint();
+ if Some(low) != hi { return false; }
+ while let Some(_) = it.next() {
+ let (xlow, xhi) = it.size_hint();
+ if low != xlow + 1 { return false; }
+ low = xlow;
+ hi = xhi;
+ if Some(low) != hi { return false; }
+ }
+ let (low, hi) = it.size_hint();
+ low == 0 && hi == Some(0)
+}
+
+// Exact size for this case, without ExactSizeIterator
+fn exact_size_for_this<I: Iterator>(mut it: I) -> bool {
+ // check every iteration
+ let (mut low, mut hi) = it.size_hint();
+ if Some(low) != hi { return false; }
+ while let Some(_) = it.next() {
+ let (xlow, xhi) = it.size_hint();
+ if low != xlow + 1 { return false; }
+ low = xlow;
+ hi = xhi;
+ if Some(low) != hi { return false; }
+ }
+ let (low, hi) = it.size_hint();
+ low == 0 && hi == Some(0)
+}
+
+/*
+ * NOTE: Range<i8> is broken!
+ * (all signed ranges are)
+#[quickcheck]
+fn size_range_i8(a: Iter<i8>) -> bool {
+ exact_size(a)
+}
+
+#[quickcheck]
+fn size_range_i16(a: Iter<i16>) -> bool {
+ exact_size(a)
+}
+
+#[quickcheck]
+fn size_range_u8(a: Iter<u8>) -> bool {
+ exact_size(a)
+}
+ */
+
+macro_rules! quickcheck {
+ // accept several property function definitions
+ // The property functions can use pattern matching and `mut` as usual
+ // in the function arguments, but the functions can not be generic.
+ {$($(#$attr:tt)* fn $fn_name:ident($($arg:tt)*) -> $ret:ty { $($code:tt)* })*} => (
+ $(
+ #[test]
+ $(#$attr)*
+ fn $fn_name() {
+ fn prop($($arg)*) -> $ret {
+ $($code)*
+ }
+ ::quickcheck::quickcheck(quickcheck!(@fn prop [] $($arg)*));
+ }
+ )*
+ );
+ // parse argument list (with patterns allowed) into prop as fn(_, _) -> _
+ (@fn $f:ident [$($t:tt)*]) => {
+ $f as fn($($t),*) -> _
+ };
+ (@fn $f:ident [$($p:tt)*] : $($tail:tt)*) => {
+ quickcheck!(@fn $f [$($p)* _] $($tail)*)
+ };
+ (@fn $f:ident [$($p:tt)*] $t:tt $($tail:tt)*) => {
+ quickcheck!(@fn $f [$($p)*] $($tail)*)
+ };
+}
+
+quickcheck! {
+
+ fn size_product(a: Iter<u16>, b: Iter<u16>) -> bool {
+ correct_size_hint(a.cartesian_product(b))
+ }
+ fn size_product3(a: Iter<u16>, b: Iter<u16>, c: Iter<u16>) -> bool {
+ correct_size_hint(iproduct!(a, b, c))
+ }
+
+ fn correct_cartesian_product3(a: Iter<u16>, b: Iter<u16>, c: Iter<u16>,
+ take_manual: usize) -> ()
+ {
+ // test correctness of iproduct through regular iteration (take)
+ // and through fold.
+ let ac = a.clone();
+ let br = &b.clone();
+ let cr = &c.clone();
+ let answer: Vec<_> = ac.flat_map(move |ea| br.clone().flat_map(move |eb| cr.clone().map(move |ec| (ea, eb, ec)))).collect();
+ let mut product_iter = iproduct!(a, b, c);
+ let mut actual = Vec::new();
+
+ actual.extend((&mut product_iter).take(take_manual));
+ if actual.len() == take_manual {
+ product_iter.fold((), |(), elt| actual.push(elt));
+ }
+ assert_eq!(answer, actual);
+ }
+
+ fn size_multi_product(a: ShiftRange) -> bool {
+ correct_size_hint(a.multi_cartesian_product())
+ }
+ fn correct_multi_product3(a: ShiftRange, take_manual: usize) -> () {
+ // Fix no. of iterators at 3
+ let a = ShiftRange { iter_count: 3, ..a };
+
+ // test correctness of MultiProduct through regular iteration (take)
+ // and through fold.
+ let mut iters = a.clone();
+ let i0 = iters.next().unwrap();
+ let i1r = &iters.next().unwrap();
+ let i2r = &iters.next().unwrap();
+ let answer: Vec<_> = i0.flat_map(move |ei0| i1r.clone().flat_map(move |ei1| i2r.clone().map(move |ei2| vec![ei0, ei1, ei2]))).collect();
+ let mut multi_product = a.clone().multi_cartesian_product();
+ let mut actual = Vec::new();
+
+ actual.extend((&mut multi_product).take(take_manual));
+ if actual.len() == take_manual {
+ multi_product.fold((), |(), elt| actual.push(elt));
+ }
+ assert_eq!(answer, actual);
+
+ assert_eq!(answer.into_iter().last(), a.clone().multi_cartesian_product().last());
+ }
+
+ #[allow(deprecated)]
+ fn size_step(a: Iter<i16, Exact>, s: usize) -> bool {
+ let mut s = s;
+ if s == 0 {
+ s += 1; // never zero
+ }
+ let filt = a.clone().dedup();
+ correct_size_hint(filt.step(s)) &&
+ exact_size(a.step(s))
+ }
+
+ #[allow(deprecated)]
+ fn equal_step(a: Iter<i16>, s: usize) -> bool {
+ let mut s = s;
+ if s == 0 {
+ s += 1; // never zero
+ }
+ let mut i = 0;
+ itertools::equal(a.clone().step(s), a.filter(|_| {
+ let keep = i % s == 0;
+ i += 1;
+ keep
+ }))
+ }
+
+ #[allow(deprecated)]
+ fn equal_step_vec(a: Vec<i16>, s: usize) -> bool {
+ let mut s = s;
+ if s == 0 {
+ s += 1; // never zero
+ }
+ let mut i = 0;
+ itertools::equal(a.iter().step(s), a.iter().filter(|_| {
+ let keep = i % s == 0;
+ i += 1;
+ keep
+ }))
+ }
+
+ fn size_multipeek(a: Iter<u16, Exact>, s: u8) -> bool {
+ let mut it = multipeek(a);
+ // peek a few times
+ for _ in 0..s {
+ it.peek();
+ }
+ exact_size(it)
+ }
+
+ fn size_peek_nth(a: Iter<u16, Exact>, s: u8) -> bool {
+ let mut it = peek_nth(a);
+ // peek a few times
+ for n in 0..s {
+ it.peek_nth(n as usize);
+ }
+ exact_size(it)
+ }
+
+ fn equal_merge(a: Vec<i16>, b: Vec<i16>) -> bool {
+ let mut sa = a.clone();
+ let mut sb = b.clone();
+ sa.sort();
+ sb.sort();
+ let mut merged = sa.clone();
+ merged.extend(sb.iter().cloned());
+ merged.sort();
+ itertools::equal(&merged, sa.iter().merge(&sb))
+ }
+ fn size_merge(a: Iter<u16>, b: Iter<u16>) -> bool {
+ correct_size_hint(a.merge(b))
+ }
+ fn size_zip(a: Iter<i16, Exact>, b: Iter<i16, Exact>, c: Iter<i16, Exact>) -> bool {
+ let filt = a.clone().dedup();
+ correct_size_hint(multizip((filt, b.clone(), c.clone()))) &&
+ exact_size(multizip((a, b, c)))
+ }
+ fn size_zip_rc(a: Iter<i16>, b: Iter<i16>) -> bool {
+ let rc = rciter(a.clone());
+ correct_size_hint(multizip((&rc, &rc, b)))
+ }
+
+ fn size_zip_macro(a: Iter<i16, Exact>, b: Iter<i16, Exact>, c: Iter<i16, Exact>) -> bool {
+ let filt = a.clone().dedup();
+ correct_size_hint(izip!(filt, b.clone(), c.clone())) &&
+ exact_size(izip!(a, b, c))
+ }
+ fn equal_kmerge(a: Vec<i16>, b: Vec<i16>, c: Vec<i16>) -> bool {
+ use itertools::free::kmerge;
+ let mut sa = a.clone();
+ let mut sb = b.clone();
+ let mut sc = c.clone();
+ sa.sort();
+ sb.sort();
+ sc.sort();
+ let mut merged = sa.clone();
+ merged.extend(sb.iter().cloned());
+ merged.extend(sc.iter().cloned());
+ merged.sort();
+ itertools::equal(merged.into_iter(), kmerge(vec![sa, sb, sc]))
+ }
+
+ // Any number of input iterators
+ fn equal_kmerge_2(mut inputs: Vec<Vec<i16>>) -> bool {
+ use itertools::free::kmerge;
+ // sort the inputs
+ for input in &mut inputs {
+ input.sort();
+ }
+ let mut merged = inputs.concat();
+ merged.sort();
+ itertools::equal(merged.into_iter(), kmerge(inputs))
+ }
+
+ // Any number of input iterators
+ fn equal_kmerge_by_ge(mut inputs: Vec<Vec<i16>>) -> bool {
+ // sort the inputs
+ for input in &mut inputs {
+ input.sort();
+ input.reverse();
+ }
+ let mut merged = inputs.concat();
+ merged.sort();
+ merged.reverse();
+ itertools::equal(merged.into_iter(),
+ inputs.into_iter().kmerge_by(|x, y| x >= y))
+ }
+
+ // Any number of input iterators
+ fn equal_kmerge_by_lt(mut inputs: Vec<Vec<i16>>) -> bool {
+ // sort the inputs
+ for input in &mut inputs {
+ input.sort();
+ }
+ let mut merged = inputs.concat();
+ merged.sort();
+ itertools::equal(merged.into_iter(),
+ inputs.into_iter().kmerge_by(|x, y| x < y))
+ }
+
+ // Any number of input iterators
+ fn equal_kmerge_by_le(mut inputs: Vec<Vec<i16>>) -> bool {
+ // sort the inputs
+ for input in &mut inputs {
+ input.sort();
+ }
+ let mut merged = inputs.concat();
+ merged.sort();
+ itertools::equal(merged.into_iter(),
+ inputs.into_iter().kmerge_by(|x, y| x <= y))
+ }
+ fn size_kmerge(a: Iter<i16>, b: Iter<i16>, c: Iter<i16>) -> bool {
+ use itertools::free::kmerge;
+ correct_size_hint(kmerge(vec![a, b, c]))
+ }
+ fn equal_zip_eq(a: Vec<i32>, b: Vec<i32>) -> bool {
+ let len = std::cmp::min(a.len(), b.len());
+ let a = &a[..len];
+ let b = &b[..len];
+ itertools::equal(zip_eq(a, b), zip(a, b))
+ }
+ fn size_zip_longest(a: Iter<i16, Exact>, b: Iter<i16, Exact>) -> bool {
+ let filt = a.clone().dedup();
+ let filt2 = b.clone().dedup();
+ correct_size_hint(filt.zip_longest(b.clone())) &&
+ correct_size_hint(a.clone().zip_longest(filt2)) &&
+ exact_size(a.zip_longest(b))
+ }
+ fn size_2_zip_longest(a: Iter<i16>, b: Iter<i16>) -> bool {
+ let it = a.clone().zip_longest(b.clone());
+ let jt = a.clone().zip_longest(b.clone());
+ itertools::equal(a.clone(),
+ it.filter_map(|elt| match elt {
+ EitherOrBoth::Both(x, _) => Some(x),
+ EitherOrBoth::Left(x) => Some(x),
+ _ => None,
+ }
+ ))
+ &&
+ itertools::equal(b.clone(),
+ jt.filter_map(|elt| match elt {
+ EitherOrBoth::Both(_, y) => Some(y),
+ EitherOrBoth::Right(y) => Some(y),
+ _ => None,
+ }
+ ))
+ }
+ fn size_interleave(a: Iter<i16>, b: Iter<i16>) -> bool {
+ correct_size_hint(a.interleave(b))
+ }
+ fn exact_interleave(a: Iter<i16, Exact>, b: Iter<i16, Exact>) -> bool {
+ exact_size_for_this(a.interleave(b))
+ }
+ fn size_interleave_shortest(a: Iter<i16>, b: Iter<i16>) -> bool {
+ correct_size_hint(a.interleave_shortest(b))
+ }
+ fn exact_interleave_shortest(a: Vec<()>, b: Vec<()>) -> bool {
+ exact_size_for_this(a.iter().interleave_shortest(&b))
+ }
+ fn size_intersperse(a: Iter<i16>, x: i16) -> bool {
+ correct_size_hint(a.intersperse(x))
+ }
+ fn equal_intersperse(a: Vec<i32>, x: i32) -> bool {
+ let mut inter = false;
+ let mut i = 0;
+ for elt in a.iter().cloned().intersperse(x) {
+ if inter {
+ if elt != x { return false }
+ } else {
+ if elt != a[i] { return false }
+ i += 1;
+ }
+ inter = !inter;
+ }
+ true
+ }
+
+ fn equal_combinations_2(a: Vec<u8>) -> bool {
+ let mut v = Vec::new();
+ for (i, x) in enumerate(&a) {
+ for y in &a[i + 1..] {
+ v.push((x, y));
+ }
+ }
+ itertools::equal(a.iter().tuple_combinations::<(_, _)>(), v)
+ }
+
+ fn collect_tuple_matches_size(a: Iter<i16>) -> bool {
+ let size = a.clone().count();
+ a.collect_tuple::<(_, _, _)>().is_some() == (size == 3)
+ }
+
+ fn correct_permutations(vals: HashSet<i32>, k: usize) -> () {
+ // Test permutations only on iterators of distinct integers, to prevent
+ // false positives.
+
+ const MAX_N: usize = 5;
+
+ let n = min(vals.len(), MAX_N);
+ let vals: HashSet<i32> = vals.into_iter().take(n).collect();
+
+ let perms = vals.iter().permutations(k);
+
+ let mut actual = HashSet::new();
+
+ for perm in perms {
+ assert_eq!(perm.len(), k);
+
+ let all_items_valid = perm.iter().all(|p| vals.contains(p));
+ assert!(all_items_valid, "perm contains value not from input: {:?}", perm);
+
+ // Check that all perm items are distinct
+ let distinct_len = {
+ let perm_set: HashSet<_> = perm.iter().collect();
+ perm_set.len()
+ };
+ assert_eq!(perm.len(), distinct_len);
+
+ // Check that the perm is new
+ assert!(actual.insert(perm.clone()), "perm already encountered: {:?}", perm);
+ }
+ }
+
+ fn permutations_lexic_order(a: usize, b: usize) -> () {
+ let a = a % 6;
+ let b = b % 6;
+
+ let n = max(a, b);
+ let k = min (a, b);
+
+ let expected_first: Vec<usize> = (0..k).collect();
+ let expected_last: Vec<usize> = ((n - k)..n).rev().collect();
+
+ let mut perms = (0..n).permutations(k);
+
+ let mut curr_perm = match perms.next() {
+ Some(p) => p,
+ None => { return; }
+ };
+
+ assert_eq!(expected_first, curr_perm);
+
+ while let Some(next_perm) = perms.next() {
+ assert!(
+ next_perm > curr_perm,
+ "next perm isn't greater-than current; next_perm={:?} curr_perm={:?} n={}",
+ next_perm, curr_perm, n
+ );
+
+ curr_perm = next_perm;
+ }
+
+ assert_eq!(expected_last, curr_perm);
+
+ }
+
+ fn permutations_count(n: usize, k: usize) -> bool {
+ let n = n % 6;
+
+ correct_count(|| (0..n).permutations(k))
+ }
+
+ fn permutations_size(a: Iter<i32>, k: usize) -> bool {
+ correct_size_hint(a.take(5).permutations(k))
+ }
+
+ fn permutations_k0_yields_once(n: usize) -> () {
+ let k = 0;
+ let expected: Vec<Vec<usize>> = vec![vec![]];
+ let actual = (0..n).permutations(k).collect_vec();
+
+ assert_eq!(expected, actual);
+ }
+}
+
+quickcheck! {
+ fn dedup_via_coalesce(a: Vec<i32>) -> bool {
+ let mut b = a.clone();
+ b.dedup();
+ itertools::equal(
+ &b,
+ a
+ .iter()
+ .coalesce(|x, y| {
+ if x==y {
+ Ok(x)
+ } else {
+ Err((x, y))
+ }
+ })
+ .fold(vec![], |mut v, n| {
+ v.push(n);
+ v
+ })
+ )
+ }
+}
+
+quickcheck! {
+ fn equal_dedup(a: Vec<i32>) -> bool {
+ let mut b = a.clone();
+ b.dedup();
+ itertools::equal(&b, a.iter().dedup())
+ }
+}
+
+quickcheck! {
+ fn equal_dedup_by(a: Vec<(i32, i32)>) -> bool {
+ let mut b = a.clone();
+ b.dedup_by(|x, y| x.0==y.0);
+ itertools::equal(&b, a.iter().dedup_by(|x, y| x.0==y.0))
+ }
+}
+
+quickcheck! {
+ fn size_dedup(a: Vec<i32>) -> bool {
+ correct_size_hint(a.iter().dedup())
+ }
+}
+
+quickcheck! {
+ fn size_dedup_by(a: Vec<(i32, i32)>) -> bool {
+ correct_size_hint(a.iter().dedup_by(|x, y| x.0==y.0))
+ }
+}
+
+quickcheck! {
+ fn exact_repeatn((n, x): (usize, i32)) -> bool {
+ let it = itertools::repeat_n(x, n);
+ exact_size(it)
+ }
+}
+
+quickcheck! {
+ fn size_put_back(a: Vec<u8>, x: Option<u8>) -> bool {
+ let mut it = put_back(a.into_iter());
+ match x {
+ Some(t) => it.put_back(t),
+ None => {}
+ }
+ correct_size_hint(it)
+ }
+}
+
+quickcheck! {
+ fn size_put_backn(a: Vec<u8>, b: Vec<u8>) -> bool {
+ let mut it = put_back_n(a.into_iter());
+ for elt in b {
+ it.put_back(elt)
+ }
+ correct_size_hint(it)
+ }
+}
+
+quickcheck! {
+ fn size_tee(a: Vec<u8>) -> bool {
+ let (mut t1, mut t2) = a.iter().tee();
+ t1.next();
+ t1.next();
+ t2.next();
+ exact_size(t1) && exact_size(t2)
+ }
+}
+
+quickcheck! {
+ fn size_tee_2(a: Vec<u8>) -> bool {
+ let (mut t1, mut t2) = a.iter().dedup().tee();
+ t1.next();
+ t1.next();
+ t2.next();
+ correct_size_hint(t1) && correct_size_hint(t2)
+ }
+}
+
+quickcheck! {
+ fn size_take_while_ref(a: Vec<u8>, stop: u8) -> bool {
+ correct_size_hint(a.iter().take_while_ref(|x| **x != stop))
+ }
+}
+
+quickcheck! {
+ fn equal_partition(a: Vec<i32>) -> bool {
+ let mut a = a;
+ let mut ap = a.clone();
+ let split_index = itertools::partition(&mut ap, |x| *x >= 0);
+ let parted = (0..split_index).all(|i| ap[i] >= 0) &&
+ (split_index..a.len()).all(|i| ap[i] < 0);
+
+ a.sort();
+ ap.sort();
+ parted && (a == ap)
+ }
+}
+
+quickcheck! {
+ fn size_combinations(it: Iter<i16>) -> bool {
+ correct_size_hint(it.tuple_combinations::<(_, _)>())
+ }
+}
+
+quickcheck! {
+ fn equal_combinations(it: Iter<i16>) -> bool {
+ let values = it.clone().collect_vec();
+ let mut cmb = it.tuple_combinations();
+ for i in 0..values.len() {
+ for j in i+1..values.len() {
+ let pair = (values[i], values[j]);
+ if pair != cmb.next().unwrap() {
+ return false;
+ }
+ }
+ }
+ cmb.next() == None
+ }
+}
+
+quickcheck! {
+ fn size_pad_tail(it: Iter<i8>, pad: u8) -> bool {
+ correct_size_hint(it.clone().pad_using(pad as usize, |_| 0)) &&
+ correct_size_hint(it.dropping(1).rev().pad_using(pad as usize, |_| 0))
+ }
+}
+
+quickcheck! {
+ fn size_pad_tail2(it: Iter<i8, Exact>, pad: u8) -> bool {
+ exact_size(it.pad_using(pad as usize, |_| 0))
+ }
+}
+
+quickcheck! {
+ fn size_powerset(it: Iter<u8, Exact>) -> bool {
+ // Powerset cardinality gets large very quickly, limit input to keep test fast.
+ correct_size_hint(it.take(12).powerset())
+ }
+}
+
+quickcheck! {
+ fn size_duplicates(it: Iter<i8>) -> bool {
+ correct_size_hint(it.duplicates())
+ }
+}
+
+quickcheck! {
+ fn size_unique(it: Iter<i8>) -> bool {
+ correct_size_hint(it.unique())
+ }
+
+ fn count_unique(it: Vec<i8>, take_first: u8) -> () {
+ let answer = {
+ let mut v = it.clone();
+ v.sort(); v.dedup();
+ v.len()
+ };
+ let mut iter = cloned(&it).unique();
+ let first_count = (&mut iter).take(take_first as usize).count();
+ let rest_count = iter.count();
+ assert_eq!(answer, first_count + rest_count);
+ }
+}
+
+quickcheck! {
+ fn fuzz_group_by_lazy_1(it: Iter<u8>) -> bool {
+ let jt = it.clone();
+ let groups = it.group_by(|k| *k);
+ let res = itertools::equal(jt, groups.into_iter().flat_map(|(_, x)| x));
+ res
+ }
+}
+
+quickcheck! {
+ fn fuzz_group_by_lazy_2(data: Vec<u8>) -> bool {
+ let groups = data.iter().group_by(|k| *k / 10);
+ let res = itertools::equal(data.iter(), groups.into_iter().flat_map(|(_, x)| x));
+ res
+ }
+}
+
+quickcheck! {
+ fn fuzz_group_by_lazy_3(data: Vec<u8>) -> bool {
+ let grouper = data.iter().group_by(|k| *k / 10);
+ let groups = grouper.into_iter().collect_vec();
+ let res = itertools::equal(data.iter(), groups.into_iter().flat_map(|(_, x)| x));
+ res
+ }
+}
+
+quickcheck! {
+ fn fuzz_group_by_lazy_duo(data: Vec<u8>, order: Vec<(bool, bool)>) -> bool {
+ let grouper = data.iter().group_by(|k| *k / 3);
+ let mut groups1 = grouper.into_iter();
+ let mut groups2 = grouper.into_iter();
+ let mut elts = Vec::<&u8>::new();
+ let mut old_groups = Vec::new();
+
+ let tup1 = |(_, b)| b;
+ for &(ord, consume_now) in &order {
+ let iter = &mut [&mut groups1, &mut groups2][ord as usize];
+ match iter.next() {
+ Some((_, gr)) => if consume_now {
+ for og in old_groups.drain(..) {
+ elts.extend(og);
+ }
+ elts.extend(gr);
+ } else {
+ old_groups.push(gr);
+ },
+ None => break,
+ }
+ }
+ for og in old_groups.drain(..) {
+ elts.extend(og);
+ }
+ for gr in groups1.map(&tup1) { elts.extend(gr); }
+ for gr in groups2.map(&tup1) { elts.extend(gr); }
+ itertools::assert_equal(&data, elts);
+ true
+ }
+}
+
+quickcheck! {
+ fn equal_chunks_lazy(a: Vec<u8>, size: u8) -> bool {
+ let mut size = size;
+ if size == 0 {
+ size += 1;
+ }
+ let chunks = a.iter().chunks(size as usize);
+ let it = a.chunks(size as usize);
+ for (a, b) in chunks.into_iter().zip(it) {
+ if !itertools::equal(a, b) {
+ return false;
+ }
+ }
+ true
+ }
+}
+
+quickcheck! {
+ fn equal_tuple_windows_1(a: Vec<u8>) -> bool {
+ let x = a.windows(1).map(|s| (&s[0], ));
+ let y = a.iter().tuple_windows::<(_,)>();
+ itertools::equal(x, y)
+ }
+
+ fn equal_tuple_windows_2(a: Vec<u8>) -> bool {
+ let x = a.windows(2).map(|s| (&s[0], &s[1]));
+ let y = a.iter().tuple_windows::<(_, _)>();
+ itertools::equal(x, y)
+ }
+
+ fn equal_tuple_windows_3(a: Vec<u8>) -> bool {
+ let x = a.windows(3).map(|s| (&s[0], &s[1], &s[2]));
+ let y = a.iter().tuple_windows::<(_, _, _)>();
+ itertools::equal(x, y)
+ }
+
+ fn equal_tuple_windows_4(a: Vec<u8>) -> bool {
+ let x = a.windows(4).map(|s| (&s[0], &s[1], &s[2], &s[3]));
+ let y = a.iter().tuple_windows::<(_, _, _, _)>();
+ itertools::equal(x, y)
+ }
+
+ fn equal_tuples_1(a: Vec<u8>) -> bool {
+ let x = a.chunks(1).map(|s| (&s[0], ));
+ let y = a.iter().tuples::<(_,)>();
+ itertools::equal(x, y)
+ }
+
+ fn equal_tuples_2(a: Vec<u8>) -> bool {
+ let x = a.chunks(2).filter(|s| s.len() == 2).map(|s| (&s[0], &s[1]));
+ let y = a.iter().tuples::<(_, _)>();
+ itertools::equal(x, y)
+ }
+
+ fn equal_tuples_3(a: Vec<u8>) -> bool {
+ let x = a.chunks(3).filter(|s| s.len() == 3).map(|s| (&s[0], &s[1], &s[2]));
+ let y = a.iter().tuples::<(_, _, _)>();
+ itertools::equal(x, y)
+ }
+
+ fn equal_tuples_4(a: Vec<u8>) -> bool {
+ let x = a.chunks(4).filter(|s| s.len() == 4).map(|s| (&s[0], &s[1], &s[2], &s[3]));
+ let y = a.iter().tuples::<(_, _, _, _)>();
+ itertools::equal(x, y)
+ }
+
+ fn exact_tuple_buffer(a: Vec<u8>) -> bool {
+ let mut iter = a.iter().tuples::<(_, _, _, _)>();
+ (&mut iter).last();
+ let buffer = iter.into_buffer();
+ assert_eq!(buffer.len(), a.len() % 4);
+ exact_size(buffer)
+ }
+}
+
+// with_position
+quickcheck! {
+ fn with_position_exact_size_1(a: Vec<u8>) -> bool {
+ exact_size_for_this(a.iter().with_position())
+ }
+ fn with_position_exact_size_2(a: Iter<u8, Exact>) -> bool {
+ exact_size_for_this(a.with_position())
+ }
+}
+
+quickcheck! {
+ fn correct_group_map_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+ let count = a.len();
+ let lookup = a.into_iter().map(|i| (i % modulo, i)).into_group_map();
+
+ assert_eq!(lookup.values().flat_map(|vals| vals.iter()).count(), count);
+
+ for (&key, vals) in lookup.iter() {
+ assert!(vals.iter().all(|&val| val % modulo == key));
+ }
+ }
+}
+
+/// A peculiar type: Equality compares both tuple items, but ordering only the
+/// first item. This is so we can check the stability property easily.
+#[derive(Clone, Debug, PartialEq, Eq)]
+struct Val(u32, u32);
+
+impl PartialOrd<Val> for Val {
+ fn partial_cmp(&self, other: &Val) -> Option<Ordering> {
+ self.0.partial_cmp(&other.0)
+ }
+}
+
+impl Ord for Val {
+ fn cmp(&self, other: &Val) -> Ordering {
+ self.0.cmp(&other.0)
+ }
+}
+
+impl qc::Arbitrary for Val {
+ fn arbitrary<G: qc::Gen>(g: &mut G) -> Self {
+ let (x, y) = <(u32, u32)>::arbitrary(g);
+ Val(x, y)
+ }
+ fn shrink(&self) -> Box<dyn Iterator<Item = Self>> {
+ Box::new((self.0, self.1).shrink().map(|(x, y)| Val(x, y)))
+ }
+}
+
+quickcheck! {
+ fn minmax(a: Vec<Val>) -> bool {
+ use itertools::MinMaxResult;
+
+
+ let minmax = a.iter().minmax();
+ let expected = match a.len() {
+ 0 => MinMaxResult::NoElements,
+ 1 => MinMaxResult::OneElement(&a[0]),
+ _ => MinMaxResult::MinMax(a.iter().min().unwrap(),
+ a.iter().max().unwrap()),
+ };
+ minmax == expected
+ }
+}
+
+quickcheck! {
+ fn minmax_f64(a: Vec<f64>) -> TestResult {
+ use itertools::MinMaxResult;
+
+ if a.iter().any(|x| x.is_nan()) {
+ return TestResult::discard();
+ }
+
+ let min = cloned(&a).fold1(f64::min);
+ let max = cloned(&a).fold1(f64::max);
+
+ let minmax = cloned(&a).minmax();
+ let expected = match a.len() {
+ 0 => MinMaxResult::NoElements,
+ 1 => MinMaxResult::OneElement(min.unwrap()),
+ _ => MinMaxResult::MinMax(min.unwrap(), max.unwrap()),
+ };
+ TestResult::from_bool(minmax == expected)
+ }
+}
+
+quickcheck! {
+ #[allow(deprecated)]
+ fn tree_fold1_f64(mut a: Vec<f64>) -> TestResult {
+ fn collapse_adjacent<F>(x: Vec<f64>, mut f: F) -> Vec<f64>
+ where F: FnMut(f64, f64) -> f64
+ {
+ let mut out = Vec::new();
+ for i in (0..x.len()).step(2) {
+ if i == x.len()-1 {
+ out.push(x[i])
+ } else {
+ out.push(f(x[i], x[i+1]));
+ }
+ }
+ out
+ }
+
+ if a.iter().any(|x| x.is_nan()) {
+ return TestResult::discard();
+ }
+
+ let actual = a.iter().cloned().tree_fold1(f64::atan2);
+
+ while a.len() > 1 {
+ a = collapse_adjacent(a, f64::atan2);
+ }
+ let expected = a.pop();
+
+ TestResult::from_bool(actual == expected)
+ }
+}
+
+quickcheck! {
+ fn exactly_one_i32(a: Vec<i32>) -> TestResult {
+ let ret = a.iter().cloned().exactly_one();
+ match a.len() {
+ 1 => TestResult::from_bool(ret.unwrap() == a[0]),
+ _ => TestResult::from_bool(ret.unwrap_err().eq(a.iter().cloned())),
+ }
+ }
+}
+
+quickcheck! {
+ fn at_most_one_i32(a: Vec<i32>) -> TestResult {
+ let ret = a.iter().cloned().at_most_one();
+ match a.len() {
+ 0 => TestResult::from_bool(ret.unwrap() == None),
+ 1 => TestResult::from_bool(ret.unwrap() == Some(a[0])),
+ _ => TestResult::from_bool(ret.unwrap_err().eq(a.iter().cloned())),
+ }
+ }
+}
+
+quickcheck! {
+ fn consistent_grouping_map_with_by(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+
+ let lookup_grouping_map = a.iter().copied().map(|i| (i % modulo, i)).into_grouping_map().collect::<Vec<_>>();
+ let lookup_grouping_map_by = a.iter().copied().into_grouping_map_by(|i| i % modulo).collect::<Vec<_>>();
+
+ assert_eq!(lookup_grouping_map, lookup_grouping_map_by);
+ }
+
+ fn correct_grouping_map_by_aggregate_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo < 2 { 2 } else { modulo } as u64; // Avoid `% 0`
+ let lookup = a.iter()
+ .map(|&b| b as u64) // Avoid overflows
+ .into_grouping_map_by(|i| i % modulo)
+ .aggregate(|acc, &key, val| {
+ assert!(val % modulo == key);
+ if val % (modulo - 1) == 0 {
+ None
+ } else {
+ Some(acc.unwrap_or(0) + val)
+ }
+ });
+
+ let group_map_lookup = a.iter()
+ .map(|&b| b as u64)
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .filter_map(|(key, vals)| {
+ vals.into_iter().fold(None, |acc, val| {
+ if val % (modulo - 1) == 0 {
+ None
+ } else {
+ Some(acc.unwrap_or(0) + val)
+ }
+ }).map(|new_val| (key, new_val))
+ })
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for m in 0..modulo {
+ assert_eq!(
+ lookup.get(&m).copied(),
+ a.iter()
+ .map(|&b| b as u64)
+ .filter(|&val| val % modulo == m)
+ .fold(None, |acc, val| {
+ if val % (modulo - 1) == 0 {
+ None
+ } else {
+ Some(acc.unwrap_or(0) + val)
+ }
+ })
+ );
+ }
+ }
+
+ fn correct_grouping_map_by_fold_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo } as u64; // Avoid `% 0`
+ let lookup = a.iter().map(|&b| b as u64) // Avoid overflows
+ .into_grouping_map_by(|i| i % modulo)
+ .fold(0u64, |acc, &key, val| {
+ assert!(val % modulo == key);
+ acc + val
+ });
+
+ let group_map_lookup = a.iter()
+ .map(|&b| b as u64)
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().fold(0u64, |acc, val| acc + val)))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &sum) in lookup.iter() {
+ assert_eq!(sum, a.iter().map(|&b| b as u64).filter(|&val| val % modulo == key).sum::<u64>());
+ }
+ }
+
+ fn correct_grouping_map_by_fold_first_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo } as u64; // Avoid `% 0`
+ let lookup = a.iter().map(|&b| b as u64) // Avoid overflows
+ .into_grouping_map_by(|i| i % modulo)
+ .fold_first(|acc, &key, val| {
+ assert!(val % modulo == key);
+ acc + val
+ });
+
+ // TODO: Swap `fold1` with stdlib's `fold_first` when it's stabilized
+ let group_map_lookup = a.iter()
+ .map(|&b| b as u64)
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().fold1(|acc, val| acc + val).unwrap()))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &sum) in lookup.iter() {
+ assert_eq!(sum, a.iter().map(|&b| b as u64).filter(|&val| val % modulo == key).sum::<u64>());
+ }
+ }
+
+ fn correct_grouping_map_by_collect_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+ let lookup_grouping_map = a.iter().copied().into_grouping_map_by(|i| i % modulo).collect::<Vec<_>>();
+ let lookup_group_map = a.iter().copied().map(|i| (i % modulo, i)).into_group_map();
+
+ assert_eq!(lookup_grouping_map, lookup_group_map);
+ }
+
+ fn correct_grouping_map_by_max_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+ let lookup = a.iter().copied().into_grouping_map_by(|i| i % modulo).max();
+
+ let group_map_lookup = a.iter().copied()
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().max().unwrap()))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &max) in lookup.iter() {
+ assert_eq!(Some(max), a.iter().copied().filter(|&val| val % modulo == key).max());
+ }
+ }
+
+ fn correct_grouping_map_by_max_by_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+ let lookup = a.iter().copied().into_grouping_map_by(|i| i % modulo).max_by(|_, v1, v2| v1.cmp(v2));
+
+ let group_map_lookup = a.iter().copied()
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().max_by(|v1, v2| v1.cmp(v2)).unwrap()))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &max) in lookup.iter() {
+ assert_eq!(Some(max), a.iter().copied().filter(|&val| val % modulo == key).max_by(|v1, v2| v1.cmp(v2)));
+ }
+ }
+
+ fn correct_grouping_map_by_max_by_key_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+ let lookup = a.iter().copied().into_grouping_map_by(|i| i % modulo).max_by_key(|_, &val| val);
+
+ let group_map_lookup = a.iter().copied()
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().max_by_key(|&val| val).unwrap()))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &max) in lookup.iter() {
+ assert_eq!(Some(max), a.iter().copied().filter(|&val| val % modulo == key).max_by_key(|&val| val));
+ }
+ }
+
+ fn correct_grouping_map_by_min_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+ let lookup = a.iter().copied().into_grouping_map_by(|i| i % modulo).min();
+
+ let group_map_lookup = a.iter().copied()
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().min().unwrap()))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &min) in lookup.iter() {
+ assert_eq!(Some(min), a.iter().copied().filter(|&val| val % modulo == key).min());
+ }
+ }
+
+ fn correct_grouping_map_by_min_by_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+ let lookup = a.iter().copied().into_grouping_map_by(|i| i % modulo).min_by(|_, v1, v2| v1.cmp(v2));
+
+ let group_map_lookup = a.iter().copied()
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().min_by(|v1, v2| v1.cmp(v2)).unwrap()))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &min) in lookup.iter() {
+ assert_eq!(Some(min), a.iter().copied().filter(|&val| val % modulo == key).min_by(|v1, v2| v1.cmp(v2)));
+ }
+ }
+
+ fn correct_grouping_map_by_min_by_key_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+ let lookup = a.iter().copied().into_grouping_map_by(|i| i % modulo).min_by_key(|_, &val| val);
+
+ let group_map_lookup = a.iter().copied()
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().min_by_key(|&val| val).unwrap()))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &min) in lookup.iter() {
+ assert_eq!(Some(min), a.iter().copied().filter(|&val| val % modulo == key).min_by_key(|&val| val));
+ }
+ }
+
+ fn correct_grouping_map_by_minmax_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+ let lookup = a.iter().copied().into_grouping_map_by(|i| i % modulo).minmax();
+
+ let group_map_lookup = a.iter().copied()
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().minmax()))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &minmax) in lookup.iter() {
+ assert_eq!(minmax, a.iter().copied().filter(|&val| val % modulo == key).minmax());
+ }
+ }
+
+ fn correct_grouping_map_by_minmax_by_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+ let lookup = a.iter().copied().into_grouping_map_by(|i| i % modulo).minmax_by(|_, v1, v2| v1.cmp(v2));
+
+ let group_map_lookup = a.iter().copied()
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().minmax_by(|v1, v2| v1.cmp(v2))))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &minmax) in lookup.iter() {
+ assert_eq!(minmax, a.iter().copied().filter(|&val| val % modulo == key).minmax_by(|v1, v2| v1.cmp(v2)));
+ }
+ }
+
+ fn correct_grouping_map_by_minmax_by_key_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo }; // Avoid `% 0`
+ let lookup = a.iter().copied().into_grouping_map_by(|i| i % modulo).minmax_by_key(|_, &val| val);
+
+ let group_map_lookup = a.iter().copied()
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().minmax_by_key(|&val| val)))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &minmax) in lookup.iter() {
+ assert_eq!(minmax, a.iter().copied().filter(|&val| val % modulo == key).minmax_by_key(|&val| val));
+ }
+ }
+
+ fn correct_grouping_map_by_sum_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = if modulo == 0 { 1 } else { modulo } as u64; // Avoid `% 0`
+ let lookup = a.iter().map(|&b| b as u64) // Avoid overflows
+ .into_grouping_map_by(|i| i % modulo)
+ .sum();
+
+ let group_map_lookup = a.iter().map(|&b| b as u64)
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().sum()))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &sum) in lookup.iter() {
+ assert_eq!(sum, a.iter().map(|&b| b as u64).filter(|&val| val % modulo == key).sum::<u64>());
+ }
+ }
+
+ fn correct_grouping_map_by_product_modulo_key(a: Vec<u8>, modulo: u8) -> () {
+ let modulo = Wrapping(if modulo == 0 { 1 } else { modulo } as u64); // Avoid `% 0`
+ let lookup = a.iter().map(|&b| Wrapping(b as u64)) // Avoid overflows
+ .into_grouping_map_by(|i| i % modulo)
+ .product();
+
+ let group_map_lookup = a.iter().map(|&b| Wrapping(b as u64))
+ .map(|i| (i % modulo, i))
+ .into_group_map()
+ .into_iter()
+ .map(|(key, vals)| (key, vals.into_iter().product::<Wrapping<u64>>()))
+ .collect::<HashMap<_,_>>();
+ assert_eq!(lookup, group_map_lookup);
+
+ for (&key, &prod) in lookup.iter() {
+ assert_eq!(
+ prod,
+ a.iter()
+ .map(|&b| Wrapping(b as u64))
+ .filter(|&val| val % modulo == key)
+ .product::<Wrapping<u64>>()
+ );
+ }
+ }
+
+ // This should check that if multiple elements are equally minimum or maximum
+ // then `max`, `min` and `minmax` pick the first minimum and the last maximum.
+ // This is to be consistent with `std::iter::max` and `std::iter::min`.
+ fn correct_grouping_map_by_min_max_minmax_order_modulo_key() -> () {
+ use itertools::MinMaxResult;
+
+ let lookup = (0..=10)
+ .into_grouping_map_by(|_| 0)
+ .max_by(|_, _, _| Ordering::Equal);
+
+ assert_eq!(lookup[&0], 10);
+
+ let lookup = (0..=10)
+ .into_grouping_map_by(|_| 0)
+ .min_by(|_, _, _| Ordering::Equal);
+
+ assert_eq!(lookup[&0], 0);
+
+ let lookup = (0..=10)
+ .into_grouping_map_by(|_| 0)
+ .minmax_by(|_, _, _| Ordering::Equal);
+
+ assert_eq!(lookup[&0], MinMaxResult::MinMax(0, 10));
+ }
+}
+
+quickcheck! {
+ #[test]
+ fn counts(nums: Vec<isize>) -> TestResult {
+ let counts = nums.iter().counts();
+ for (&item, &count) in counts.iter() {
+ if count <= 0 {
+ return TestResult::failed();
+ }
+ if count != nums.iter().filter(|&x| x == item).count() {
+ return TestResult::failed();
+ }
+ }
+ for item in nums.iter() {
+ if !counts.contains_key(item) {
+ return TestResult::failed();
+ }
+ }
+ TestResult::passed()
+ }
+}
+
+quickcheck! {
+ fn test_double_ended_zip_2(a: Vec<u8>, b: Vec<u8>) -> TestResult {
+ let mut x =
+ multizip((a.clone().into_iter(), b.clone().into_iter()))
+ .collect_vec();
+ x.reverse();
+
+ let y =
+ multizip((a.into_iter(), b.into_iter()))
+ .rfold(Vec::new(), |mut vec, e| { vec.push(e); vec });
+
+ TestResult::from_bool(itertools::equal(x, y))
+ }
+
+ fn test_double_ended_zip_3(a: Vec<u8>, b: Vec<u8>, c: Vec<u8>) -> TestResult {
+ let mut x =
+ multizip((a.clone().into_iter(), b.clone().into_iter(), c.clone().into_iter()))
+ .collect_vec();
+ x.reverse();
+
+ let y =
+ multizip((a.into_iter(), b.into_iter(), c.into_iter()))
+ .rfold(Vec::new(), |mut vec, e| { vec.push(e); vec });
+
+ TestResult::from_bool(itertools::equal(x, y))
+ }
+}
+
+
+fn is_fused<I: Iterator>(mut it: I) -> bool
+{
+ while let Some(_) = it.next() {}
+ for _ in 0..10{
+ if it.next().is_some(){
+ return false;
+ }
+ }
+ true
+}
+
+quickcheck! {
+ fn fused_combination(a: Iter<i16>) -> bool
+ {
+ is_fused(a.clone().combinations(1)) &&
+ is_fused(a.combinations(3))
+ }
+
+ fn fused_combination_with_replacement(a: Iter<i16>) -> bool
+ {
+ is_fused(a.clone().combinations_with_replacement(1)) &&
+ is_fused(a.combinations_with_replacement(3))
+ }
+
+ fn fused_tuple_combination(a: Iter<i16>) -> bool
+ {
+ is_fused(a.clone().fuse().tuple_combinations::<(_,)>()) &&
+ is_fused(a.fuse().tuple_combinations::<(_,_,_)>())
+ }
+
+ fn fused_unique(a: Iter<i16>) -> bool
+ {
+ is_fused(a.fuse().unique())
+ }
+
+ fn fused_unique_by(a: Iter<i16>) -> bool
+ {
+ is_fused(a.fuse().unique_by(|x| x % 100))
+ }
+
+ fn fused_interleave_shortest(a: Iter<i16>, b: Iter<i16>) -> bool
+ {
+ !is_fused(a.clone().interleave_shortest(b.clone())) &&
+ is_fused(a.fuse().interleave_shortest(b.fuse()))
+ }
+
+ fn fused_product(a: Iter<i16>, b: Iter<i16>) -> bool
+ {
+ is_fused(a.fuse().cartesian_product(b.fuse()))
+ }
+
+ fn fused_merge(a: Iter<i16>, b: Iter<i16>) -> bool
+ {
+ is_fused(a.fuse().merge(b.fuse()))
+ }
+
+ fn fused_filter_ok(a: Iter<i16>) -> bool
+ {
+ is_fused(a.map(|x| if x % 2 == 0 {Ok(x)} else {Err(x)} )
+ .filter_ok(|x| x % 3 == 0)
+ .fuse())
+ }
+
+ fn fused_filter_map_ok(a: Iter<i16>) -> bool
+ {
+ is_fused(a.map(|x| if x % 2 == 0 {Ok(x)} else {Err(x)} )
+ .filter_map_ok(|x| if x % 3 == 0 {Some(x / 3)} else {None})
+ .fuse())
+ }
+
+ fn fused_positions(a: Iter<i16>) -> bool
+ {
+ !is_fused(a.clone().positions(|x|x%2==0)) &&
+ is_fused(a.fuse().positions(|x|x%2==0))
+ }
+
+ fn fused_update(a: Iter<i16>) -> bool
+ {
+ !is_fused(a.clone().update(|x|*x+=1)) &&
+ is_fused(a.fuse().update(|x|*x+=1))
+ }
+
+ fn fused_tuple_windows(a: Iter<i16>) -> bool
+ {
+ is_fused(a.fuse().tuple_windows::<(_,_)>())
+ }
+
+ fn fused_pad_using(a: Iter<i16>) -> bool
+ {
+ is_fused(a.fuse().pad_using(100,|_|0))
+ }
+}
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-10 23:50:57 +0000