Initial import of itertools-0.9.0.
Bug: 155309706
Change-Id: Id790c146e836f0eadfb0d8a103cbe2d226a598c3
diff --git a/tests/adaptors_no_collect.rs b/tests/adaptors_no_collect.rs
new file mode 100644
index 0000000..a47f906
--- /dev/null
+++ b/tests/adaptors_no_collect.rs
@@ -0,0 +1,47 @@
+use itertools::Itertools;
+
+struct PanickingCounter {
+ curr: usize,
+ max: usize,
+}
+
+impl Iterator for PanickingCounter {
+ type Item = ();
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.curr += 1;
+
+ if self.curr == self.max {
+ panic!(
+ "Input iterator reached maximum of {} suggesting collection by adaptor",
+ self.max
+ );
+ }
+
+ Some(())
+ }
+}
+
+fn no_collect_test<A, T>(to_adaptor: T)
+ where A: Iterator, T: Fn(PanickingCounter) -> A
+{
+ let counter = PanickingCounter { curr: 0, max: 10_000 };
+ let adaptor = to_adaptor(counter);
+
+ for _ in adaptor.take(5) {}
+}
+
+#[test]
+fn permutations_no_collect() {
+ no_collect_test(|iter| iter.permutations(5))
+}
+
+#[test]
+fn combinations_no_collect() {
+ no_collect_test(|iter| iter.combinations(5))
+}
+
+#[test]
+fn combinations_with_replacement_no_collect() {
+ no_collect_test(|iter| iter.combinations_with_replacement(5))
+}
\ No newline at end of file
diff --git a/tests/fold_specialization.rs b/tests/fold_specialization.rs
new file mode 100644
index 0000000..a984b40
--- /dev/null
+++ b/tests/fold_specialization.rs
@@ -0,0 +1,13 @@
+use itertools::Itertools;
+
+#[test]
+fn specialization_intersperse() {
+ let mut iter = (1..2).intersperse(0);
+ iter.clone().for_each(|x| assert_eq!(Some(x), iter.next()));
+
+ let mut iter = (1..3).intersperse(0);
+ iter.clone().for_each(|x| assert_eq!(Some(x), iter.next()));
+
+ let mut iter = (1..4).intersperse(0);
+ iter.clone().for_each(|x| assert_eq!(Some(x), iter.next()));
+}
diff --git a/tests/merge_join.rs b/tests/merge_join.rs
new file mode 100644
index 0000000..3280b7d
--- /dev/null
+++ b/tests/merge_join.rs
@@ -0,0 +1,108 @@
+use itertools::EitherOrBoth;
+use itertools::free::merge_join_by;
+
+#[test]
+fn empty() {
+ let left: Vec<u32> = vec![];
+ let right: Vec<u32> = vec![];
+ let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![];
+ let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
+ .collect::<Vec<_>>();
+ assert_eq!(expected_result, actual_result);
+}
+
+#[test]
+fn left_only() {
+ let left: Vec<u32> = vec![1,2,3];
+ let right: Vec<u32> = vec![];
+ let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+ EitherOrBoth::Left(1),
+ EitherOrBoth::Left(2),
+ EitherOrBoth::Left(3)
+ ];
+ let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
+ .collect::<Vec<_>>();
+ assert_eq!(expected_result, actual_result);
+}
+
+#[test]
+fn right_only() {
+ let left: Vec<u32> = vec![];
+ let right: Vec<u32> = vec![1,2,3];
+ let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+ EitherOrBoth::Right(1),
+ EitherOrBoth::Right(2),
+ EitherOrBoth::Right(3)
+ ];
+ let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
+ .collect::<Vec<_>>();
+ assert_eq!(expected_result, actual_result);
+}
+
+#[test]
+fn first_left_then_right() {
+ let left: Vec<u32> = vec![1,2,3];
+ let right: Vec<u32> = vec![4,5,6];
+ let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+ EitherOrBoth::Left(1),
+ EitherOrBoth::Left(2),
+ EitherOrBoth::Left(3),
+ EitherOrBoth::Right(4),
+ EitherOrBoth::Right(5),
+ EitherOrBoth::Right(6)
+ ];
+ let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
+ .collect::<Vec<_>>();
+ assert_eq!(expected_result, actual_result);
+}
+
+#[test]
+fn first_right_then_left() {
+ let left: Vec<u32> = vec![4,5,6];
+ let right: Vec<u32> = vec![1,2,3];
+ let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+ EitherOrBoth::Right(1),
+ EitherOrBoth::Right(2),
+ EitherOrBoth::Right(3),
+ EitherOrBoth::Left(4),
+ EitherOrBoth::Left(5),
+ EitherOrBoth::Left(6)
+ ];
+ let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
+ .collect::<Vec<_>>();
+ assert_eq!(expected_result, actual_result);
+}
+
+#[test]
+fn interspersed_left_and_right() {
+ let left: Vec<u32> = vec![1,3,5];
+ let right: Vec<u32> = vec![2,4,6];
+ let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+ EitherOrBoth::Left(1),
+ EitherOrBoth::Right(2),
+ EitherOrBoth::Left(3),
+ EitherOrBoth::Right(4),
+ EitherOrBoth::Left(5),
+ EitherOrBoth::Right(6)
+ ];
+ let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
+ .collect::<Vec<_>>();
+ assert_eq!(expected_result, actual_result);
+}
+
+#[test]
+fn overlapping_left_and_right() {
+ let left: Vec<u32> = vec![1,3,4,6];
+ let right: Vec<u32> = vec![2,3,4,5];
+ let expected_result: Vec<EitherOrBoth<u32, u32>> = vec![
+ EitherOrBoth::Left(1),
+ EitherOrBoth::Right(2),
+ EitherOrBoth::Both(3, 3),
+ EitherOrBoth::Both(4, 4),
+ EitherOrBoth::Right(5),
+ EitherOrBoth::Left(6)
+ ];
+ let actual_result = merge_join_by(left, right, |l, r| l.cmp(r))
+ .collect::<Vec<_>>();
+ assert_eq!(expected_result, actual_result);
+}
diff --git a/tests/peeking_take_while.rs b/tests/peeking_take_while.rs
new file mode 100644
index 0000000..a114702
--- /dev/null
+++ b/tests/peeking_take_while.rs
@@ -0,0 +1,50 @@
+use itertools::Itertools;
+use itertools::{put_back, put_back_n};
+
+#[test]
+fn peeking_take_while_peekable() {
+ let mut r = (0..10).peekable();
+ r.peeking_take_while(|x| *x <= 3).count();
+ assert_eq!(r.next(), Some(4));
+}
+
+#[test]
+fn peeking_take_while_put_back() {
+ let mut r = put_back(0..10);
+ r.peeking_take_while(|x| *x <= 3).count();
+ assert_eq!(r.next(), Some(4));
+ r.peeking_take_while(|_| true).count();
+ assert_eq!(r.next(), None);
+}
+
+#[test]
+fn peeking_take_while_put_back_n() {
+ let mut r = put_back_n(6..10);
+ for elt in (0..6).rev() {
+ r.put_back(elt);
+ }
+ r.peeking_take_while(|x| *x <= 3).count();
+ assert_eq!(r.next(), Some(4));
+ r.peeking_take_while(|_| true).count();
+ assert_eq!(r.next(), None);
+}
+
+#[test]
+fn peeking_take_while_slice_iter() {
+ let v = [1, 2, 3, 4, 5, 6];
+ let mut r = v.iter();
+ r.peeking_take_while(|x| **x <= 3).count();
+ assert_eq!(r.next(), Some(&4));
+ r.peeking_take_while(|_| true).count();
+ assert_eq!(r.next(), None);
+}
+
+#[test]
+fn peeking_take_while_slice_iter_rev() {
+ let v = [1, 2, 3, 4, 5, 6];
+ let mut r = v.iter().rev();
+ r.peeking_take_while(|x| **x >= 3).count();
+ assert_eq!(r.next(), Some(&2));
+ r.peeking_take_while(|_| true).count();
+ assert_eq!(r.next(), None);
+}
diff --git a/tests/quick.rs b/tests/quick.rs
new file mode 100644
index 0000000..683ba7a
--- /dev/null
+++ b/tests/quick.rs
@@ -0,0 +1,1157 @@
+//! 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::ops::Range;
+use std::cmp::{max, min, Ordering};
+use std::collections::HashSet;
+use itertools::Itertools;
+use itertools::{
+ multizip,
+ EitherOrBoth,
+ iproduct,
+ izip,
+};
+use itertools::free::{
+ cloned,
+ enumerate,
+ multipeek,
+ 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 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 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_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())),
+ }
+ }
+}
diff --git a/tests/specializations.rs b/tests/specializations.rs
new file mode 100644
index 0000000..ef51bbe
--- /dev/null
+++ b/tests/specializations.rs
@@ -0,0 +1,149 @@
+use itertools::{EitherOrBoth, Itertools};
+use std::fmt::Debug;
+use std::ops::BitXor;
+use quickcheck::quickcheck;
+
+struct Unspecialized<I>(I);
+impl<I> Iterator for Unspecialized<I>
+where
+ I: Iterator,
+{
+ type Item = I::Item;
+
+ #[inline(always)]
+ fn next(&mut self) -> Option<I::Item> {
+ self.0.next()
+ }
+
+ #[inline(always)]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.0.size_hint()
+ }
+}
+
+fn check_specialized<'a, V, IterItem, Iter, F>(iterator: &Iter, mapper: F)
+where
+ V: Eq + Debug,
+ IterItem: 'a,
+ Iter: Iterator<Item = IterItem> + Clone + 'a,
+ F: Fn(Box<dyn Iterator<Item = IterItem> + 'a>) -> V,
+{
+ assert_eq!(
+ mapper(Box::new(Unspecialized(iterator.clone()))),
+ mapper(Box::new(iterator.clone()))
+ )
+}
+
+fn check_specialized_count_last_nth_sizeh<'a, IterItem, Iter>(
+ it: &Iter,
+ known_expected_size: Option<usize>,
+) where
+ IterItem: 'a + Eq + Debug,
+ Iter: Iterator<Item = IterItem> + Clone + 'a,
+{
+ let size = it.clone().count();
+ if let Some(expected_size) = known_expected_size {
+ assert_eq!(size, expected_size);
+ }
+ check_specialized(it, |i| i.count());
+ check_specialized(it, |i| i.last());
+ for n in 0..size + 2 {
+ check_specialized(it, |mut i| i.nth(n));
+ }
+ let mut it_sh = it.clone();
+ for n in 0..size + 2 {
+ let len = it_sh.clone().count();
+ let (min, max) = it_sh.size_hint();
+ assert_eq!((size - n.min(size)), len);
+ assert!(min <= len);
+ if let Some(max) = max {
+ assert!(len <= max);
+ }
+ it_sh.next();
+ }
+}
+
+fn check_specialized_fold_xor<'a, IterItem, Iter>(it: &Iter)
+where
+ IterItem: 'a
+ + BitXor
+ + Eq
+ + Debug
+ + BitXor<<IterItem as BitXor>::Output, Output = <IterItem as BitXor>::Output>
+ + Clone,
+ <IterItem as BitXor>::Output:
+ BitXor<Output = <IterItem as BitXor>::Output> + Eq + Debug + Clone,
+ Iter: Iterator<Item = IterItem> + Clone + 'a,
+{
+ check_specialized(it, |mut i| {
+ let first = i.next().map(|f| f.clone() ^ (f.clone() ^ f));
+ i.fold(first, |acc, v: IterItem| acc.map(move |a| v ^ a))
+ });
+}
+
+fn put_back_test(test_vec: Vec<i32>, known_expected_size: Option<usize>) {
+ {
+ // Lexical lifetimes support
+ let pb = itertools::put_back(test_vec.iter());
+ check_specialized_count_last_nth_sizeh(&pb, known_expected_size);
+ check_specialized_fold_xor(&pb);
+ }
+
+ let mut pb = itertools::put_back(test_vec.into_iter());
+ pb.put_back(1);
+ check_specialized_count_last_nth_sizeh(&pb, known_expected_size.map(|x| x + 1));
+ check_specialized_fold_xor(&pb)
+}
+
+#[test]
+fn put_back() {
+ put_back_test(vec![7, 4, 1], Some(3));
+}
+
+quickcheck! {
+ fn put_back_qc(test_vec: Vec<i32>) -> () {
+ put_back_test(test_vec, None)
+ }
+}
+
+fn merge_join_by_test(i1: Vec<usize>, i2: Vec<usize>, known_expected_size: Option<usize>) {
+ let i1 = i1.into_iter();
+ let i2 = i2.into_iter();
+ let mjb = i1.clone().merge_join_by(i2.clone(), std::cmp::Ord::cmp);
+ check_specialized_count_last_nth_sizeh(&mjb, known_expected_size);
+ // Rust 1.24 compatibility:
+ fn eob_left_z(eob: EitherOrBoth<usize, usize>) -> usize {
+ eob.left().unwrap_or(0)
+ }
+ fn eob_right_z(eob: EitherOrBoth<usize, usize>) -> usize {
+ eob.left().unwrap_or(0)
+ }
+ fn eob_both_z(eob: EitherOrBoth<usize, usize>) -> usize {
+ let (a, b) = eob.both().unwrap_or((0, 0));
+ assert_eq!(a, b);
+ a
+ }
+ check_specialized_fold_xor(&mjb.clone().map(eob_left_z));
+ check_specialized_fold_xor(&mjb.clone().map(eob_right_z));
+ check_specialized_fold_xor(&mjb.clone().map(eob_both_z));
+
+ // And the other way around
+ let mjb = i2.merge_join_by(i1, std::cmp::Ord::cmp);
+ check_specialized_count_last_nth_sizeh(&mjb, known_expected_size);
+ check_specialized_fold_xor(&mjb.clone().map(eob_left_z));
+ check_specialized_fold_xor(&mjb.clone().map(eob_right_z));
+ check_specialized_fold_xor(&mjb.clone().map(eob_both_z));
+}
+
+#[test]
+fn merge_join_by() {
+ let i1 = vec![1, 3, 5, 7, 8, 9];
+ let i2 = vec![0, 3, 4, 5];
+ merge_join_by_test(i1, i2, Some(8));
+}
+
+quickcheck! {
+ fn merge_join_by_qc(i1: Vec<usize>, i2: Vec<usize>) -> () {
+ merge_join_by_test(i1, i2, None)
+ }
+}
diff --git a/tests/test_core.rs b/tests/test_core.rs
new file mode 100644
index 0000000..5861653
--- /dev/null
+++ b/tests/test_core.rs
@@ -0,0 +1,272 @@
+//! Licensed under the Apache License, Version 2.0
+//! http://www.apache.org/licenses/LICENSE-2.0 or the MIT license
+//! http://opensource.org/licenses/MIT, at your
+//! option. This file may not be copied, modified, or distributed
+//! except according to those terms.
+#![no_std]
+
+use core::iter;
+use itertools as it;
+use crate::it::Itertools;
+use crate::it::interleave;
+use crate::it::multizip;
+use crate::it::free::put_back;
+use crate::it::iproduct;
+use crate::it::izip;
+
+#[test]
+fn product2() {
+ let s = "αβ";
+
+ let mut prod = iproduct!(s.chars(), 0..2);
+ assert!(prod.next() == Some(('α', 0)));
+ assert!(prod.next() == Some(('α', 1)));
+ assert!(prod.next() == Some(('β', 0)));
+ assert!(prod.next() == Some(('β', 1)));
+ assert!(prod.next() == None);
+}
+
+#[test]
+fn product_temporary() {
+ for (_x, _y, _z) in iproduct!(
+ [0, 1, 2].iter().cloned(),
+ [0, 1, 2].iter().cloned(),
+ [0, 1, 2].iter().cloned())
+ {
+ // ok
+ }
+}
+
+
+#[test]
+fn izip_macro() {
+ let mut zip = izip!(2..3);
+ assert!(zip.next() == Some(2));
+ assert!(zip.next().is_none());
+
+ let mut zip = izip!(0..3, 0..2, 0..2i8);
+ for i in 0..2 {
+ assert!((i as usize, i, i as i8) == zip.next().unwrap());
+ }
+ assert!(zip.next().is_none());
+
+ let xs: [isize; 0] = [];
+ let mut zip = izip!(0..3, 0..2, 0..2i8, &xs);
+ assert!(zip.next().is_none());
+}
+
+#[test]
+fn izip2() {
+ let _zip1: iter::Zip<_, _> = izip!(1.., 2..);
+ let _zip2: iter::Zip<_, _> = izip!(1.., 2.., );
+}
+
+#[test]
+fn izip3() {
+ let mut zip: iter::Map<iter::Zip<_, _>, _> = izip!(0..3, 0..2, 0..2i8);
+ for i in 0..2 {
+ assert!((i as usize, i, i as i8) == zip.next().unwrap());
+ }
+ assert!(zip.next().is_none());
+}
+
+#[test]
+fn multizip3() {
+ let mut zip = multizip((0..3, 0..2, 0..2i8));
+ for i in 0..2 {
+ assert!((i as usize, i, i as i8) == zip.next().unwrap());
+ }
+ assert!(zip.next().is_none());
+
+ let xs: [isize; 0] = [];
+ let mut zip = multizip((0..3, 0..2, 0..2i8, xs.iter()));
+ assert!(zip.next().is_none());
+
+ for (_, _, _, _, _) in multizip((0..3, 0..2, xs.iter(), &xs, xs.to_vec())) {
+ /* test compiles */
+ }
+}
+
+#[test]
+fn write_to() {
+ let xs = [7, 9, 8];
+ let mut ys = [0; 5];
+ let cnt = ys.iter_mut().set_from(xs.iter().map(|x| *x));
+ assert!(cnt == xs.len());
+ assert!(ys == [7, 9, 8, 0, 0]);
+
+ let cnt = ys.iter_mut().set_from(0..10);
+ assert!(cnt == ys.len());
+ assert!(ys == [0, 1, 2, 3, 4]);
+}
+
+#[test]
+fn test_interleave() {
+ let xs: [u8; 0] = [];
+ let ys = [7u8, 9, 8, 10];
+ let zs = [2u8, 77];
+ let it = interleave(xs.iter(), ys.iter());
+ it::assert_equal(it, ys.iter());
+
+ let rs = [7u8, 2, 9, 77, 8, 10];
+ let it = interleave(ys.iter(), zs.iter());
+ it::assert_equal(it, rs.iter());
+}
+
+#[allow(deprecated)]
+#[test]
+fn foreach() {
+ let xs = [1i32, 2, 3];
+ let mut sum = 0;
+ xs.iter().foreach(|elt| sum += *elt);
+ assert!(sum == 6);
+}
+
+#[test]
+fn dropping() {
+ let xs = [1, 2, 3];
+ let mut it = xs.iter().dropping(2);
+ assert_eq!(it.next(), Some(&3));
+ assert!(it.next().is_none());
+ let mut it = xs.iter().dropping(5);
+ assert!(it.next().is_none());
+}
+
+#[test]
+fn batching() {
+ let xs = [0, 1, 2, 1, 3];
+ let ys = [(0, 1), (2, 1)];
+
+ // An iterator that gathers elements up in pairs
+ let pit = xs.iter().cloned().batching(|it| {
+ match it.next() {
+ None => None,
+ Some(x) => match it.next() {
+ None => None,
+ Some(y) => Some((x, y)),
+ }
+ }
+ });
+ it::assert_equal(pit, ys.iter().cloned());
+}
+
+#[test]
+fn test_put_back() {
+ let xs = [0, 1, 1, 1, 2, 1, 3, 3];
+ let mut pb = put_back(xs.iter().cloned());
+ pb.next();
+ pb.put_back(1);
+ pb.put_back(0);
+ it::assert_equal(pb, xs.iter().cloned());
+}
+
+#[allow(deprecated)]
+#[test]
+fn step() {
+ it::assert_equal((0..10).step(1), 0..10);
+ it::assert_equal((0..10).step(2), (0..10).filter(|x: &i32| *x % 2 == 0));
+ it::assert_equal((0..10).step(10), 0..1);
+}
+
+#[allow(deprecated)]
+#[test]
+fn merge() {
+ it::assert_equal((0..10).step(2).merge((1..10).step(2)), 0..10);
+}
+
+
+#[test]
+fn repeatn() {
+ let s = "α";
+ let mut it = it::repeat_n(s, 3);
+ assert_eq!(it.len(), 3);
+ assert_eq!(it.next(), Some(s));
+ assert_eq!(it.next(), Some(s));
+ assert_eq!(it.next(), Some(s));
+ assert_eq!(it.next(), None);
+ assert_eq!(it.next(), None);
+}
+
+#[test]
+fn count_clones() {
+ // Check that RepeatN only clones N - 1 times.
+
+ use core::cell::Cell;
+ #[derive(PartialEq, Debug)]
+ struct Foo {
+ n: Cell<usize>
+ }
+
+ impl Clone for Foo
+ {
+ fn clone(&self) -> Self
+ {
+ let n = self.n.get();
+ self.n.set(n + 1);
+ Foo { n: Cell::new(n + 1) }
+ }
+ }
+
+
+ for n in 0..10 {
+ let f = Foo{n: Cell::new(0)};
+ let it = it::repeat_n(f, n);
+ // drain it
+ let last = it.last();
+ if n == 0 {
+ assert_eq!(last, None);
+ } else {
+ assert_eq!(last, Some(Foo{n: Cell::new(n - 1)}));
+ }
+ }
+}
+
+#[test]
+fn part() {
+ let mut data = [7, 1, 1, 9, 1, 1, 3];
+ let i = it::partition(&mut data, |elt| *elt >= 3);
+ assert_eq!(i, 3);
+ assert_eq!(data, [7, 3, 9, 1, 1, 1, 1]);
+
+ let i = it::partition(&mut data, |elt| *elt == 1);
+ assert_eq!(i, 4);
+ assert_eq!(data, [1, 1, 1, 1, 9, 3, 7]);
+
+ let mut data = [1, 2, 3, 4, 5, 6, 7, 8, 9];
+ let i = it::partition(&mut data, |elt| *elt % 3 == 0);
+ assert_eq!(i, 3);
+ assert_eq!(data, [9, 6, 3, 4, 5, 2, 7, 8, 1]);
+}
+
+#[test]
+fn tree_fold1() {
+ for i in 0..100 {
+ assert_eq!((0..i).tree_fold1(|x, y| x + y), (0..i).fold1(|x, y| x + y));
+ }
+}
+
+#[test]
+fn exactly_one() {
+ assert_eq!((0..10).filter(|&x| x == 2).exactly_one().unwrap(), 2);
+ assert!((0..10).filter(|&x| x > 1 && x < 4).exactly_one().unwrap_err().eq(2..4));
+ assert!((0..10).filter(|&x| x > 1 && x < 5).exactly_one().unwrap_err().eq(2..5));
+ assert!((0..10).filter(|&_| false).exactly_one().unwrap_err().eq(0..0));
+}
+
+#[test]
+fn sum1() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+ assert_eq!(v[..0].iter().cloned().sum1::<i32>(), None);
+ assert_eq!(v[1..2].iter().cloned().sum1::<i32>(), Some(1));
+ assert_eq!(v[1..3].iter().cloned().sum1::<i32>(), Some(3));
+ assert_eq!(v.iter().cloned().sum1::<i32>(), Some(55));
+}
+
+#[test]
+fn product1() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+ assert_eq!(v[..0].iter().cloned().product1::<i32>(), None);
+ assert_eq!(v[..1].iter().cloned().product1::<i32>(), Some(0));
+ assert_eq!(v[1..3].iter().cloned().product1::<i32>(), Some(2));
+ assert_eq!(v[1..5].iter().cloned().product1::<i32>(), Some(24));
+}
diff --git a/tests/test_std.rs b/tests/test_std.rs
new file mode 100644
index 0000000..ba07784
--- /dev/null
+++ b/tests/test_std.rs
@@ -0,0 +1,793 @@
+use permutohedron;
+use itertools as it;
+use crate::it::Itertools;
+use crate::it::multizip;
+use crate::it::multipeek;
+use crate::it::free::rciter;
+use crate::it::free::put_back_n;
+use crate::it::FoldWhile;
+use crate::it::cloned;
+use crate::it::iproduct;
+use crate::it::izip;
+
+#[test]
+fn product3() {
+ let prod = iproduct!(0..3, 0..2, 0..2);
+ assert_eq!(prod.size_hint(), (12, Some(12)));
+ let v = prod.collect_vec();
+ for i in 0..3 {
+ for j in 0..2 {
+ for k in 0..2 {
+ assert!((i, j, k) == v[(i * 2 * 2 + j * 2 + k) as usize]);
+ }
+ }
+ }
+ for (_, _, _, _) in iproduct!(0..3, 0..2, 0..2, 0..3) {
+ /* test compiles */
+ }
+}
+
+#[test]
+fn interleave_shortest() {
+ let v0: Vec<i32> = vec![0, 2, 4];
+ let v1: Vec<i32> = vec![1, 3, 5, 7];
+ let it = v0.into_iter().interleave_shortest(v1.into_iter());
+ assert_eq!(it.size_hint(), (6, Some(6)));
+ assert_eq!(it.collect_vec(), vec![0, 1, 2, 3, 4, 5]);
+
+ let v0: Vec<i32> = vec![0, 2, 4, 6, 8];
+ let v1: Vec<i32> = vec![1, 3, 5];
+ let it = v0.into_iter().interleave_shortest(v1.into_iter());
+ assert_eq!(it.size_hint(), (7, Some(7)));
+ assert_eq!(it.collect_vec(), vec![0, 1, 2, 3, 4, 5, 6]);
+
+ let i0 = ::std::iter::repeat(0);
+ let v1: Vec<_> = vec![1, 3, 5];
+ let it = i0.interleave_shortest(v1.into_iter());
+ assert_eq!(it.size_hint(), (7, Some(7)));
+
+ let v0: Vec<_> = vec![0, 2, 4];
+ let i1 = ::std::iter::repeat(1);
+ let it = v0.into_iter().interleave_shortest(i1);
+ assert_eq!(it.size_hint(), (6, Some(6)));
+}
+
+
+#[test]
+fn unique_by() {
+ let xs = ["aaa", "bbbbb", "aa", "ccc", "bbbb", "aaaaa", "cccc"];
+ let ys = ["aaa", "bbbbb", "ccc"];
+ it::assert_equal(ys.iter(), xs.iter().unique_by(|x| x[..2].to_string()));
+}
+
+#[test]
+fn unique() {
+ let xs = [0, 1, 2, 3, 2, 1, 3];
+ let ys = [0, 1, 2, 3];
+ it::assert_equal(ys.iter(), xs.iter().unique());
+ let xs = [0, 1];
+ let ys = [0, 1];
+ it::assert_equal(ys.iter(), xs.iter().unique());
+}
+
+#[test]
+fn intersperse() {
+ let xs = ["a", "", "b", "c"];
+ let v: Vec<&str> = xs.iter().map(|x| x.clone()).intersperse(", ").collect();
+ let text: String = v.concat();
+ assert_eq!(text, "a, , b, c".to_string());
+
+ let ys = [0, 1, 2, 3];
+ let mut it = ys[..0].iter().map(|x| *x).intersperse(1);
+ assert!(it.next() == None);
+}
+
+#[test]
+fn dedup() {
+ let xs = [0, 1, 1, 1, 2, 1, 3, 3];
+ let ys = [0, 1, 2, 1, 3];
+ it::assert_equal(ys.iter(), xs.iter().dedup());
+ let xs = [0, 0, 0, 0, 0];
+ let ys = [0];
+ it::assert_equal(ys.iter(), xs.iter().dedup());
+
+ let xs = [0, 1, 1, 1, 2, 1, 3, 3];
+ let ys = [0, 1, 2, 1, 3];
+ let mut xs_d = Vec::new();
+ xs.iter().dedup().fold((), |(), &elt| xs_d.push(elt));
+ assert_eq!(&xs_d, &ys);
+}
+
+#[test]
+fn dedup_by() {
+ let xs = [(0, 0), (0, 1), (1, 1), (2, 1), (0, 2), (3, 1), (0, 3), (1, 3)];
+ let ys = [(0, 0), (0, 1), (0, 2), (3, 1), (0, 3)];
+ it::assert_equal(ys.iter(), xs.iter().dedup_by(|x, y| x.1==y.1));
+ let xs = [(0, 1), (0, 2), (0, 3), (0, 4), (0, 5)];
+ let ys = [(0, 1)];
+ it::assert_equal(ys.iter(), xs.iter().dedup_by(|x, y| x.0==y.0));
+
+ let xs = [(0, 0), (0, 1), (1, 1), (2, 1), (0, 2), (3, 1), (0, 3), (1, 3)];
+ let ys = [(0, 0), (0, 1), (0, 2), (3, 1), (0, 3)];
+ let mut xs_d = Vec::new();
+ xs.iter().dedup_by(|x, y| x.1==y.1).fold((), |(), &elt| xs_d.push(elt));
+ assert_eq!(&xs_d, &ys);
+}
+
+#[test]
+fn all_equal() {
+ assert!("".chars().all_equal());
+ assert!("A".chars().all_equal());
+ assert!(!"AABBCCC".chars().all_equal());
+ assert!("AAAAAAA".chars().all_equal());
+ for (_key, mut sub) in &"AABBCCC".chars().group_by(|&x| x) {
+ assert!(sub.all_equal());
+ }
+}
+
+#[test]
+fn test_put_back_n() {
+ let xs = [0, 1, 1, 1, 2, 1, 3, 3];
+ let mut pb = put_back_n(xs.iter().cloned());
+ pb.next();
+ pb.next();
+ pb.put_back(1);
+ pb.put_back(0);
+ it::assert_equal(pb, xs.iter().cloned());
+}
+
+#[test]
+fn tee() {
+ let xs = [0, 1, 2, 3];
+ let (mut t1, mut t2) = xs.iter().cloned().tee();
+ assert_eq!(t1.next(), Some(0));
+ assert_eq!(t2.next(), Some(0));
+ assert_eq!(t1.next(), Some(1));
+ assert_eq!(t1.next(), Some(2));
+ assert_eq!(t1.next(), Some(3));
+ assert_eq!(t1.next(), None);
+ assert_eq!(t2.next(), Some(1));
+ assert_eq!(t2.next(), Some(2));
+ assert_eq!(t1.next(), None);
+ assert_eq!(t2.next(), Some(3));
+ assert_eq!(t2.next(), None);
+ assert_eq!(t1.next(), None);
+ assert_eq!(t2.next(), None);
+
+ let (t1, t2) = xs.iter().cloned().tee();
+ it::assert_equal(t1, xs.iter().cloned());
+ it::assert_equal(t2, xs.iter().cloned());
+
+ let (t1, t2) = xs.iter().cloned().tee();
+ it::assert_equal(t1.zip(t2), xs.iter().cloned().zip(xs.iter().cloned()));
+}
+
+
+#[test]
+fn test_rciter() {
+ let xs = [0, 1, 1, 1, 2, 1, 3, 5, 6];
+
+ let mut r1 = rciter(xs.iter().cloned());
+ let mut r2 = r1.clone();
+ assert_eq!(r1.next(), Some(0));
+ assert_eq!(r2.next(), Some(1));
+ let mut z = r1.zip(r2);
+ assert_eq!(z.next(), Some((1, 1)));
+ assert_eq!(z.next(), Some((2, 1)));
+ assert_eq!(z.next(), Some((3, 5)));
+ assert_eq!(z.next(), None);
+
+ // test intoiterator
+ let r1 = rciter(0..5);
+ let mut z = izip!(&r1, r1);
+ assert_eq!(z.next(), Some((0, 1)));
+}
+
+#[allow(deprecated)]
+#[test]
+fn trait_pointers() {
+ struct ByRef<'r, I: ?Sized>(&'r mut I) ;
+
+ impl<'r, X, I: ?Sized> Iterator for ByRef<'r, I> where
+ I: 'r + Iterator<Item=X>
+ {
+ type Item = X;
+ fn next(&mut self) -> Option<X>
+ {
+ self.0.next()
+ }
+ }
+
+ let mut it = Box::new(0..10) as Box<dyn Iterator<Item=i32>>;
+ assert_eq!(it.next(), Some(0));
+
+ {
+ /* make sure foreach works on non-Sized */
+ let jt: &mut dyn Iterator<Item = i32> = &mut *it;
+ assert_eq!(jt.next(), Some(1));
+
+ {
+ let mut r = ByRef(jt);
+ assert_eq!(r.next(), Some(2));
+ }
+
+ assert_eq!(jt.find_position(|x| *x == 4), Some((1, 4)));
+ jt.foreach(|_| ());
+ }
+}
+
+#[test]
+fn merge_by() {
+ let odd : Vec<(u32, &str)> = vec![(1, "hello"), (3, "world"), (5, "!")];
+ let even = vec![(2, "foo"), (4, "bar"), (6, "baz")];
+ let expected = vec![(1, "hello"), (2, "foo"), (3, "world"), (4, "bar"), (5, "!"), (6, "baz")];
+ let results = odd.iter().merge_by(even.iter(), |a, b| a.0 <= b.0);
+ it::assert_equal(results, expected.iter());
+}
+
+#[test]
+fn merge_by_btree() {
+ use std::collections::BTreeMap;
+ let mut bt1 = BTreeMap::new();
+ bt1.insert("hello", 1);
+ bt1.insert("world", 3);
+ let mut bt2 = BTreeMap::new();
+ bt2.insert("foo", 2);
+ bt2.insert("bar", 4);
+ let results = bt1.into_iter().merge_by(bt2.into_iter(), |a, b| a.0 <= b.0 );
+ let expected = vec![("bar", 4), ("foo", 2), ("hello", 1), ("world", 3)];
+ it::assert_equal(results, expected.into_iter());
+}
+
+#[allow(deprecated)]
+#[test]
+fn kmerge() {
+ let its = (0..4).map(|s| (s..10).step(4));
+
+ it::assert_equal(its.kmerge(), 0..10);
+}
+
+#[allow(deprecated)]
+#[test]
+fn kmerge_2() {
+ let its = vec![3, 2, 1, 0].into_iter().map(|s| (s..10).step(4));
+
+ it::assert_equal(its.kmerge(), 0..10);
+}
+
+#[test]
+fn kmerge_empty() {
+ let its = (0..4).map(|_| 0..0);
+ assert_eq!(its.kmerge().next(), None);
+}
+
+#[test]
+fn kmerge_size_hint() {
+ let its = (0..5).map(|_| (0..10));
+ assert_eq!(its.kmerge().size_hint(), (50, Some(50)));
+}
+
+#[test]
+fn kmerge_empty_size_hint() {
+ let its = (0..5).map(|_| (0..0));
+ assert_eq!(its.kmerge().size_hint(), (0, Some(0)));
+}
+
+#[test]
+fn join() {
+ let many = [1, 2, 3];
+ let one = [1];
+ let none: Vec<i32> = vec![];
+
+ assert_eq!(many.iter().join(", "), "1, 2, 3");
+ assert_eq!( one.iter().join(", "), "1");
+ assert_eq!(none.iter().join(", "), "");
+}
+
+#[test]
+fn sorted_by() {
+ let sc = [3, 4, 1, 2].iter().cloned().sorted_by(|&a, &b| {
+ a.cmp(&b)
+ });
+ it::assert_equal(sc, vec![1, 2, 3, 4]);
+
+ let v = (0..5).sorted_by(|&a, &b| a.cmp(&b).reverse());
+ it::assert_equal(v, vec![4, 3, 2, 1, 0]);
+}
+
+#[test]
+fn sorted_by_key() {
+ let sc = [3, 4, 1, 2].iter().cloned().sorted_by_key(|&x| x);
+ it::assert_equal(sc, vec![1, 2, 3, 4]);
+
+ let v = (0..5).sorted_by_key(|&x| -x);
+ it::assert_equal(v, vec![4, 3, 2, 1, 0]);
+}
+
+#[test]
+fn test_multipeek() {
+ let nums = vec![1u8,2,3,4,5];
+
+ let mp = multipeek(nums.iter().map(|&x| x));
+ assert_eq!(nums, mp.collect::<Vec<_>>());
+
+ let mut mp = multipeek(nums.iter().map(|&x| x));
+ assert_eq!(mp.peek(), Some(&1));
+ assert_eq!(mp.next(), Some(1));
+ assert_eq!(mp.peek(), Some(&2));
+ assert_eq!(mp.peek(), Some(&3));
+ assert_eq!(mp.next(), Some(2));
+ assert_eq!(mp.peek(), Some(&3));
+ assert_eq!(mp.peek(), Some(&4));
+ assert_eq!(mp.peek(), Some(&5));
+ assert_eq!(mp.peek(), None);
+ assert_eq!(mp.next(), Some(3));
+ assert_eq!(mp.next(), Some(4));
+ assert_eq!(mp.peek(), Some(&5));
+ assert_eq!(mp.peek(), None);
+ assert_eq!(mp.next(), Some(5));
+ assert_eq!(mp.next(), None);
+ assert_eq!(mp.peek(), None);
+
+}
+
+#[test]
+fn test_multipeek_reset() {
+ let data = [1, 2, 3, 4];
+
+ let mut mp = multipeek(cloned(&data));
+ assert_eq!(mp.peek(), Some(&1));
+ assert_eq!(mp.next(), Some(1));
+ assert_eq!(mp.peek(), Some(&2));
+ assert_eq!(mp.peek(), Some(&3));
+ mp.reset_peek();
+ assert_eq!(mp.peek(), Some(&2));
+ assert_eq!(mp.next(), Some(2));
+}
+
+#[test]
+fn test_multipeek_peeking_next() {
+ use crate::it::PeekingNext;
+ let nums = vec![1u8,2,3,4,5,6,7];
+
+ let mut mp = multipeek(nums.iter().map(|&x| x));
+ assert_eq!(mp.peeking_next(|&x| x != 0), Some(1));
+ assert_eq!(mp.next(), Some(2));
+ assert_eq!(mp.peek(), Some(&3));
+ assert_eq!(mp.peek(), Some(&4));
+ assert_eq!(mp.peeking_next(|&x| x == 3), Some(3));
+ assert_eq!(mp.peek(), Some(&4));
+ assert_eq!(mp.peeking_next(|&x| x != 4), None);
+ assert_eq!(mp.peeking_next(|&x| x == 4), Some(4));
+ assert_eq!(mp.peek(), Some(&5));
+ assert_eq!(mp.peek(), Some(&6));
+ assert_eq!(mp.peeking_next(|&x| x != 5), None);
+ assert_eq!(mp.peek(), Some(&7));
+ assert_eq!(mp.peeking_next(|&x| x == 5), Some(5));
+ assert_eq!(mp.peeking_next(|&x| x == 6), Some(6));
+ assert_eq!(mp.peek(), Some(&7));
+ assert_eq!(mp.peek(), None);
+ assert_eq!(mp.next(), Some(7));
+ assert_eq!(mp.peek(), None);
+}
+
+#[test]
+fn pad_using() {
+ it::assert_equal((0..0).pad_using(1, |_| 1), 1..2);
+
+ let v: Vec<usize> = vec![0, 1, 2];
+ let r = v.into_iter().pad_using(5, |n| n);
+ it::assert_equal(r, vec![0, 1, 2, 3, 4]);
+
+ let v: Vec<usize> = vec![0, 1, 2];
+ let r = v.into_iter().pad_using(1, |_| panic!());
+ it::assert_equal(r, vec![0, 1, 2]);
+}
+
+#[test]
+fn group_by() {
+ for (ch1, sub) in &"AABBCCC".chars().group_by(|&x| x) {
+ for ch2 in sub {
+ assert_eq!(ch1, ch2);
+ }
+ }
+
+ for (ch1, sub) in &"AAABBBCCCCDDDD".chars().group_by(|&x| x) {
+ for ch2 in sub {
+ assert_eq!(ch1, ch2);
+ if ch1 == 'C' {
+ break;
+ }
+ }
+ }
+
+ let toupper = |ch: &char| ch.to_uppercase().nth(0).unwrap();
+
+ // try all possible orderings
+ for indices in permutohedron::Heap::new(&mut [0, 1, 2, 3]) {
+ let groups = "AaaBbbccCcDDDD".chars().group_by(&toupper);
+ let mut subs = groups.into_iter().collect_vec();
+
+ for &idx in &indices[..] {
+ let (key, text) = match idx {
+ 0 => ('A', "Aaa".chars()),
+ 1 => ('B', "Bbb".chars()),
+ 2 => ('C', "ccCc".chars()),
+ 3 => ('D', "DDDD".chars()),
+ _ => unreachable!(),
+ };
+ assert_eq!(key, subs[idx].0);
+ it::assert_equal(&mut subs[idx].1, text);
+ }
+ }
+
+ let groups = "AAABBBCCCCDDDD".chars().group_by(|&x| x);
+ let mut subs = groups.into_iter().map(|(_, g)| g).collect_vec();
+
+ let sd = subs.pop().unwrap();
+ let sc = subs.pop().unwrap();
+ let sb = subs.pop().unwrap();
+ let sa = subs.pop().unwrap();
+ for (a, b, c, d) in multizip((sa, sb, sc, sd)) {
+ assert_eq!(a, 'A');
+ assert_eq!(b, 'B');
+ assert_eq!(c, 'C');
+ assert_eq!(d, 'D');
+ }
+
+ // check that the key closure is called exactly n times
+ {
+ let mut ntimes = 0;
+ let text = "AABCCC";
+ for (_, sub) in &text.chars().group_by(|&x| { ntimes += 1; x}) {
+ for _ in sub {
+ }
+ }
+ assert_eq!(ntimes, text.len());
+ }
+
+ {
+ let mut ntimes = 0;
+ let text = "AABCCC";
+ for _ in &text.chars().group_by(|&x| { ntimes += 1; x}) {
+ }
+ assert_eq!(ntimes, text.len());
+ }
+
+ {
+ let text = "ABCCCDEEFGHIJJKK";
+ let gr = text.chars().group_by(|&x| x);
+ it::assert_equal(gr.into_iter().flat_map(|(_, sub)| sub), text.chars());
+ }
+}
+
+#[test]
+fn group_by_lazy_2() {
+ let data = vec![0, 1];
+ let groups = data.iter().group_by(|k| *k);
+ let gs = groups.into_iter().collect_vec();
+ it::assert_equal(data.iter(), gs.into_iter().flat_map(|(_k, g)| g));
+
+ let data = vec![0, 1, 1, 0, 0];
+ let groups = data.iter().group_by(|k| *k);
+ let mut gs = groups.into_iter().collect_vec();
+ gs[1..].reverse();
+ it::assert_equal(&[0, 0, 0, 1, 1], gs.into_iter().flat_map(|(_, g)| g));
+
+ let grouper = data.iter().group_by(|k| *k);
+ let mut groups = Vec::new();
+ for (k, group) in &grouper {
+ if *k == 1 {
+ groups.push(group);
+ }
+ }
+ it::assert_equal(&mut groups[0], &[1, 1]);
+
+ let data = vec![0, 0, 0, 1, 1, 0, 0, 2, 2, 3, 3];
+ let grouper = data.iter().group_by(|k| *k);
+ let mut groups = Vec::new();
+ for (i, (_, group)) in grouper.into_iter().enumerate() {
+ if i < 2 {
+ groups.push(group);
+ } else if i < 4 {
+ for _ in group {
+ }
+ } else {
+ groups.push(group);
+ }
+ }
+ it::assert_equal(&mut groups[0], &[0, 0, 0]);
+ it::assert_equal(&mut groups[1], &[1, 1]);
+ it::assert_equal(&mut groups[2], &[3, 3]);
+
+ // use groups as chunks
+ let data = vec![0, 0, 0, 1, 1, 0, 0, 2, 2, 3, 3];
+ let mut i = 0;
+ let grouper = data.iter().group_by(move |_| { let k = i / 3; i += 1; k });
+ for (i, group) in &grouper {
+ match i {
+ 0 => it::assert_equal(group, &[0, 0, 0]),
+ 1 => it::assert_equal(group, &[1, 1, 0]),
+ 2 => it::assert_equal(group, &[0, 2, 2]),
+ 3 => it::assert_equal(group, &[3, 3]),
+ _ => unreachable!(),
+ }
+ }
+}
+
+#[test]
+fn group_by_lazy_3() {
+ // test consuming each group on the lap after it was produced
+ let data = vec![0, 0, 0, 1, 1, 0, 0, 1, 1, 2, 2];
+ let grouper = data.iter().group_by(|elt| *elt);
+ let mut last = None;
+ for (key, group) in &grouper {
+ if let Some(gr) = last.take() {
+ for elt in gr {
+ assert!(elt != key && i32::abs(elt - key) == 1);
+ }
+ }
+ last = Some(group);
+ }
+}
+
+#[test]
+fn chunks() {
+ let data = vec![0, 0, 0, 1, 1, 0, 0, 2, 2, 3, 3];
+ let grouper = data.iter().chunks(3);
+ for (i, chunk) in grouper.into_iter().enumerate() {
+ match i {
+ 0 => it::assert_equal(chunk, &[0, 0, 0]),
+ 1 => it::assert_equal(chunk, &[1, 1, 0]),
+ 2 => it::assert_equal(chunk, &[0, 2, 2]),
+ 3 => it::assert_equal(chunk, &[3, 3]),
+ _ => unreachable!(),
+ }
+ }
+}
+
+#[test]
+fn concat_empty() {
+ let data: Vec<Vec<()>> = Vec::new();
+ assert_eq!(data.into_iter().concat(), Vec::new())
+}
+
+#[test]
+fn concat_non_empty() {
+ let data = vec![vec![1,2,3], vec![4,5,6], vec![7,8,9]];
+ assert_eq!(data.into_iter().concat(), vec![1,2,3,4,5,6,7,8,9])
+}
+
+#[test]
+fn combinations() {
+ assert!((1..3).combinations(5).next().is_none());
+
+ let it = (1..3).combinations(2);
+ it::assert_equal(it, vec![
+ vec![1, 2],
+ ]);
+
+ let it = (1..5).combinations(2);
+ it::assert_equal(it, vec![
+ vec![1, 2],
+ vec![1, 3],
+ vec![1, 4],
+ vec![2, 3],
+ vec![2, 4],
+ vec![3, 4],
+ ]);
+
+ it::assert_equal((0..0).tuple_combinations::<(_, _)>(), <Vec<_>>::new());
+ it::assert_equal((0..1).tuple_combinations::<(_, _)>(), <Vec<_>>::new());
+ it::assert_equal((0..2).tuple_combinations::<(_, _)>(), vec![(0, 1)]);
+
+ it::assert_equal((0..0).combinations(2), <Vec<Vec<_>>>::new());
+ it::assert_equal((0..1).combinations(1), vec![vec![0]]);
+ it::assert_equal((0..2).combinations(1), vec![vec![0], vec![1]]);
+ it::assert_equal((0..2).combinations(2), vec![vec![0, 1]]);
+}
+
+#[test]
+fn combinations_of_too_short() {
+ for i in 1..10 {
+ assert!((0..0).combinations(i).next().is_none());
+ assert!((0..i - 1).combinations(i).next().is_none());
+ }
+}
+
+
+#[test]
+fn combinations_zero() {
+ it::assert_equal((1..3).combinations(0), vec![vec![]]);
+ it::assert_equal((0..0).combinations(0), vec![vec![]]);
+}
+
+#[test]
+fn permutations_zero() {
+ it::assert_equal((1..3).permutations(0), vec![vec![]]);
+ it::assert_equal((0..0).permutations(0), vec![vec![]]);
+}
+
+#[test]
+fn combinations_with_replacement() {
+ // Pool smaller than n
+ it::assert_equal((0..1).combinations_with_replacement(2), vec![vec![0, 0]]);
+ // Pool larger than n
+ it::assert_equal(
+ (0..3).combinations_with_replacement(2),
+ vec![
+ vec![0, 0],
+ vec![0, 1],
+ vec![0, 2],
+ vec![1, 1],
+ vec![1, 2],
+ vec![2, 2],
+ ],
+ );
+ // Zero size
+ it::assert_equal(
+ (0..3).combinations_with_replacement(0),
+ vec![vec![]],
+ );
+ // Zero size on empty pool
+ it::assert_equal(
+ (0..0).combinations_with_replacement(0),
+ vec![vec![]],
+ );
+ // Empty pool
+ it::assert_equal(
+ (0..0).combinations_with_replacement(2),
+ <Vec<Vec<_>>>::new(),
+ );
+}
+
+#[test]
+fn diff_mismatch() {
+ let a = vec![1, 2, 3, 4];
+ let b = vec![1.0, 5.0, 3.0, 4.0];
+ let b_map = b.into_iter().map(|f| f as i32);
+ let diff = it::diff_with(a.iter(), b_map, |a, b| *a == b);
+
+ assert!(match diff {
+ Some(it::Diff::FirstMismatch(1, _, from_diff)) =>
+ from_diff.collect::<Vec<_>>() == vec![5, 3, 4],
+ _ => false,
+ });
+}
+
+#[test]
+fn diff_longer() {
+ let a = vec![1, 2, 3, 4];
+ let b = vec![1.0, 2.0, 3.0, 4.0, 5.0, 6.0];
+ let b_map = b.into_iter().map(|f| f as i32);
+ let diff = it::diff_with(a.iter(), b_map, |a, b| *a == b);
+
+ assert!(match diff {
+ Some(it::Diff::Longer(_, remaining)) =>
+ remaining.collect::<Vec<_>>() == vec![5, 6],
+ _ => false,
+ });
+}
+
+#[test]
+fn diff_shorter() {
+ let a = vec![1, 2, 3, 4];
+ let b = vec![1.0, 2.0];
+ let b_map = b.into_iter().map(|f| f as i32);
+ let diff = it::diff_with(a.iter(), b_map, |a, b| *a == b);
+
+ assert!(match diff {
+ Some(it::Diff::Shorter(len, _)) => len == 2,
+ _ => false,
+ });
+}
+
+#[test]
+fn minmax() {
+ use std::cmp::Ordering;
+ use crate::it::MinMaxResult;
+
+ // 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)
+ }
+ }
+
+ assert_eq!(None::<Option<u32>>.iter().minmax(), MinMaxResult::NoElements);
+
+ assert_eq!(Some(1u32).iter().minmax(), MinMaxResult::OneElement(&1));
+
+ let data = vec![Val(0, 1), Val(2, 0), Val(0, 2), Val(1, 0), Val(2, 1)];
+
+ let minmax = data.iter().minmax();
+ assert_eq!(minmax, MinMaxResult::MinMax(&Val(0, 1), &Val(2, 1)));
+
+ let (min, max) = data.iter().minmax_by_key(|v| v.1).into_option().unwrap();
+ assert_eq!(min, &Val(2, 0));
+ assert_eq!(max, &Val(0, 2));
+
+ let (min, max) = data.iter().minmax_by(|x, y| x.1.cmp(&y.1)).into_option().unwrap();
+ assert_eq!(min, &Val(2, 0));
+ assert_eq!(max, &Val(0, 2));
+}
+
+#[test]
+fn format() {
+ let data = [0, 1, 2, 3];
+ let ans1 = "0, 1, 2, 3";
+ let ans2 = "0--1--2--3";
+
+ let t1 = format!("{}", data.iter().format(", "));
+ assert_eq!(t1, ans1);
+ let t2 = format!("{:?}", data.iter().format("--"));
+ assert_eq!(t2, ans2);
+
+ let dataf = [1.1, 2.71828, -22.];
+ let t3 = format!("{:.2e}", dataf.iter().format(", "));
+ assert_eq!(t3, "1.10e0, 2.72e0, -2.20e1");
+}
+
+#[test]
+fn while_some() {
+ let ns = (1..10).map(|x| if x % 5 != 0 { Some(x) } else { None })
+ .while_some();
+ it::assert_equal(ns, vec![1, 2, 3, 4]);
+}
+
+#[allow(deprecated)]
+#[test]
+fn fold_while() {
+ let mut iterations = 0;
+ let vec = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+ let sum = vec.into_iter().fold_while(0, |acc, item| {
+ iterations += 1;
+ let new_sum = acc.clone() + item;
+ if new_sum <= 20 {
+ FoldWhile::Continue(new_sum)
+ } else {
+ FoldWhile::Done(acc)
+ }
+ }).into_inner();
+ assert_eq!(iterations, 6);
+ assert_eq!(sum, 15);
+}
+
+#[test]
+fn tree_fold1() {
+ let x = [
+ "",
+ "0",
+ "0 1 x",
+ "0 1 x 2 x",
+ "0 1 x 2 3 x x",
+ "0 1 x 2 3 x x 4 x",
+ "0 1 x 2 3 x x 4 5 x x",
+ "0 1 x 2 3 x x 4 5 x 6 x x",
+ "0 1 x 2 3 x x 4 5 x 6 7 x x x",
+ "0 1 x 2 3 x x 4 5 x 6 7 x x x 8 x",
+ "0 1 x 2 3 x x 4 5 x 6 7 x x x 8 9 x x",
+ "0 1 x 2 3 x x 4 5 x 6 7 x x x 8 9 x 10 x x",
+ "0 1 x 2 3 x x 4 5 x 6 7 x x x 8 9 x 10 11 x x x",
+ "0 1 x 2 3 x x 4 5 x 6 7 x x x 8 9 x 10 11 x x 12 x x",
+ "0 1 x 2 3 x x 4 5 x 6 7 x x x 8 9 x 10 11 x x 12 13 x x x",
+ "0 1 x 2 3 x x 4 5 x 6 7 x x x 8 9 x 10 11 x x 12 13 x 14 x x x",
+ "0 1 x 2 3 x x 4 5 x 6 7 x x x 8 9 x 10 11 x x 12 13 x 14 15 x x x x",
+ ];
+ for (i, &s) in x.iter().enumerate() {
+ let expected = if s == "" { None } else { Some(s.to_string()) };
+ let num_strings = (0..i).map(|x| x.to_string());
+ let actual = num_strings.tree_fold1(|a, b| format!("{} {} x", a, b));
+ assert_eq!(actual, expected);
+ }
+}
diff --git a/tests/tuples.rs b/tests/tuples.rs
new file mode 100644
index 0000000..9fc8b3c
--- /dev/null
+++ b/tests/tuples.rs
@@ -0,0 +1,86 @@
+use itertools::Itertools;
+
+#[test]
+fn tuples() {
+ let v = [1, 2, 3, 4, 5];
+ let mut iter = v.iter().cloned().tuples();
+ assert_eq!(Some((1,)), iter.next());
+ assert_eq!(Some((2,)), iter.next());
+ assert_eq!(Some((3,)), iter.next());
+ assert_eq!(Some((4,)), iter.next());
+ assert_eq!(Some((5,)), iter.next());
+ assert_eq!(None, iter.next());
+ assert_eq!(None, iter.into_buffer().next());
+
+ let mut iter = v.iter().cloned().tuples();
+ assert_eq!(Some((1, 2)), iter.next());
+ assert_eq!(Some((3, 4)), iter.next());
+ assert_eq!(None, iter.next());
+ itertools::assert_equal(vec![5], iter.into_buffer());
+
+ let mut iter = v.iter().cloned().tuples();
+ assert_eq!(Some((1, 2, 3)), iter.next());
+ assert_eq!(None, iter.next());
+ itertools::assert_equal(vec![4, 5], iter.into_buffer());
+
+ let mut iter = v.iter().cloned().tuples();
+ assert_eq!(Some((1, 2, 3, 4)), iter.next());
+ assert_eq!(None, iter.next());
+ itertools::assert_equal(vec![5], iter.into_buffer());
+}
+
+#[test]
+fn tuple_windows() {
+ let v = [1, 2, 3, 4, 5];
+
+ let mut iter = v.iter().cloned().tuple_windows();
+ assert_eq!(Some((1,)), iter.next());
+ assert_eq!(Some((2,)), iter.next());
+ assert_eq!(Some((3,)), iter.next());
+
+ let mut iter = v.iter().cloned().tuple_windows();
+ assert_eq!(Some((1, 2)), iter.next());
+ assert_eq!(Some((2, 3)), iter.next());
+ assert_eq!(Some((3, 4)), iter.next());
+ assert_eq!(Some((4, 5)), iter.next());
+ assert_eq!(None, iter.next());
+
+ let mut iter = v.iter().cloned().tuple_windows();
+ assert_eq!(Some((1, 2, 3)), iter.next());
+ assert_eq!(Some((2, 3, 4)), iter.next());
+ assert_eq!(Some((3, 4, 5)), iter.next());
+ assert_eq!(None, iter.next());
+
+ let mut iter = v.iter().cloned().tuple_windows();
+ assert_eq!(Some((1, 2, 3, 4)), iter.next());
+ assert_eq!(Some((2, 3, 4, 5)), iter.next());
+ assert_eq!(None, iter.next());
+
+ let v = [1, 2, 3];
+ let mut iter = v.iter().cloned().tuple_windows::<(_, _, _, _)>();
+ assert_eq!(None, iter.next());
+}
+
+#[test]
+fn next_tuple() {
+ let v = [1, 2, 3, 4, 5];
+ let mut iter = v.iter();
+ assert_eq!(iter.next_tuple().map(|(&x, &y)| (x, y)), Some((1, 2)));
+ assert_eq!(iter.next_tuple().map(|(&x, &y)| (x, y)), Some((3, 4)));
+ assert_eq!(iter.next_tuple::<(_, _)>(), None);
+}
+
+#[test]
+fn collect_tuple() {
+ let v = [1, 2];
+ let iter = v.iter().cloned();
+ assert_eq!(iter.collect_tuple(), Some((1, 2)));
+
+ let v = [1];
+ let iter = v.iter().cloned();
+ assert_eq!(iter.collect_tuple::<(_, _)>(), None);
+
+ let v = [1, 2, 3];
+ let iter = v.iter().cloned();
+ assert_eq!(iter.collect_tuple::<(_, _)>(), None);
+}
diff --git a/tests/zip.rs b/tests/zip.rs
new file mode 100644
index 0000000..b1af52c
--- /dev/null
+++ b/tests/zip.rs
@@ -0,0 +1,63 @@
+use itertools::Itertools;
+use itertools::EitherOrBoth::{Both, Left, Right};
+use itertools::free::zip_eq;
+
+#[test]
+fn zip_longest_fused() {
+ let a = [Some(1), None, Some(3), Some(4)];
+ let b = [1, 2, 3];
+
+ let unfused = a.iter().batching(|it| *it.next().unwrap())
+ .zip_longest(b.iter().cloned());
+ itertools::assert_equal(unfused,
+ vec![Both(1, 1), Right(2), Right(3)]);
+}
+
+#[test]
+fn test_zip_longest_size_hint() {
+ let c = (1..10).cycle();
+ let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+ let v2 = &[10, 11, 12];
+
+ assert_eq!(c.zip_longest(v.iter()).size_hint(), (std::usize::MAX, None));
+
+ assert_eq!(v.iter().zip_longest(v2.iter()).size_hint(), (10, Some(10)));
+}
+
+#[test]
+fn test_double_ended_zip_longest() {
+ let xs = [1, 2, 3, 4, 5, 6];
+ let ys = [1, 2, 3, 7];
+ let a = xs.iter().map(|&x| x);
+ let b = ys.iter().map(|&x| x);
+ let mut it = a.zip_longest(b);
+ assert_eq!(it.next(), Some(Both(1, 1)));
+ assert_eq!(it.next(), Some(Both(2, 2)));
+ assert_eq!(it.next_back(), Some(Left(6)));
+ assert_eq!(it.next_back(), Some(Left(5)));
+ assert_eq!(it.next_back(), Some(Both(4, 7)));
+ assert_eq!(it.next(), Some(Both(3, 3)));
+ assert_eq!(it.next(), None);
+}
+
+
+#[should_panic]
+#[test]
+fn zip_eq_panic1()
+{
+ let a = [1, 2];
+ let b = [1, 2, 3];
+
+ zip_eq(&a, &b).count();
+}
+
+#[should_panic]
+#[test]
+fn zip_eq_panic2()
+{
+ let a: [i32; 0] = [];
+ let b = [1, 2, 3];
+
+ zip_eq(&a, &b).count();
+}
+
