library/std/src/collections/hash/set/tests.rs

use super::HashSet;
use crate::hash::RandomState;
use crate::panic::{AssertUnwindSafe, catch_unwind};
use crate::sync::Arc;
use crate::sync::atomic::{AtomicU32, Ordering};

#[test]
fn test_zero_capacities() {
    type HS = HashSet<i32>;

    let s = HS::new();
    assert_eq!(s.capacity(), 0);

    let s = HS::default();
    assert_eq!(s.capacity(), 0);

    let s = HS::with_hasher(RandomState::new());
    assert_eq!(s.capacity(), 0);

    let s = HS::with_capacity(0);
    assert_eq!(s.capacity(), 0);

    let s = HS::with_capacity_and_hasher(0, RandomState::new());
    assert_eq!(s.capacity(), 0);

    let mut s = HS::new();
    s.insert(1);
    s.insert(2);
    s.remove(&1);
    s.remove(&2);
    s.shrink_to_fit();
    assert_eq!(s.capacity(), 0);

    let mut s = HS::new();
    s.reserve(0);
    assert_eq!(s.capacity(), 0);
}

#[test]
fn test_disjoint() {
    let mut xs = HashSet::new();
    let mut ys = HashSet::new();
    assert!(xs.is_disjoint(&ys));
    assert!(ys.is_disjoint(&xs));
    assert!(xs.insert(5));
    assert!(ys.insert(11));
    assert!(xs.is_disjoint(&ys));
    assert!(ys.is_disjoint(&xs));
    assert!(xs.insert(7));
    assert!(xs.insert(19));
    assert!(xs.insert(4));
    assert!(ys.insert(2));
    assert!(ys.insert(-11));
    assert!(xs.is_disjoint(&ys));
    assert!(ys.is_disjoint(&xs));
    assert!(ys.insert(7));
    assert!(!xs.is_disjoint(&ys));
    assert!(!ys.is_disjoint(&xs));
}

#[test]
fn test_subset_and_superset() {
    let mut a = HashSet::new();
    assert!(a.insert(0));
    assert!(a.insert(5));
    assert!(a.insert(11));
    assert!(a.insert(7));

    let mut b = HashSet::new();
    assert!(b.insert(0));
    assert!(b.insert(7));
    assert!(b.insert(19));
    assert!(b.insert(250));
    assert!(b.insert(11));
    assert!(b.insert(200));

    assert!(!a.is_subset(&b));
    assert!(!a.is_superset(&b));
    assert!(!b.is_subset(&a));
    assert!(!b.is_superset(&a));

    assert!(b.insert(5));

    assert!(a.is_subset(&b));
    assert!(!a.is_superset(&b));
    assert!(!b.is_subset(&a));
    assert!(b.is_superset(&a));
}

#[test]
fn test_iterate() {
    let mut a = HashSet::new();
    for i in 0..32 {
        assert!(a.insert(i));
    }
    let mut observed: u32 = 0;
    for k in &a {
        observed |= 1 << *k;
    }
    assert_eq!(observed, 0xFFFF_FFFF);
}

#[test]
fn test_intersection() {
    let mut a = HashSet::new();
    let mut b = HashSet::new();
    assert!(a.intersection(&b).next().is_none());

    assert!(a.insert(11));
    assert!(a.insert(1));
    assert!(a.insert(3));
    assert!(a.insert(77));
    assert!(a.insert(103));
    assert!(a.insert(5));
    assert!(a.insert(-5));

    assert!(b.insert(2));
    assert!(b.insert(11));
    assert!(b.insert(77));
    assert!(b.insert(-9));
    assert!(b.insert(-42));
    assert!(b.insert(5));
    assert!(b.insert(3));

    let mut i = 0;
    let expected = [3, 5, 11, 77];
    for x in a.intersection(&b) {
        assert!(expected.contains(x));
        i += 1
    }
    assert_eq!(i, expected.len());

    assert!(a.insert(9)); // make a bigger than b

    i = 0;
    for x in a.intersection(&b) {
        assert!(expected.contains(x));
        i += 1
    }
    assert_eq!(i, expected.len());

    i = 0;
    for x in b.intersection(&a) {
        assert!(expected.contains(x));
        i += 1
    }
    assert_eq!(i, expected.len());
}

#[test]
fn test_difference() {
    let mut a = HashSet::new();
    let mut b = HashSet::new();

    assert!(a.insert(1));
    assert!(a.insert(3));
    assert!(a.insert(5));
    assert!(a.insert(9));
    assert!(a.insert(11));

    assert!(b.insert(3));
    assert!(b.insert(9));

    let mut i = 0;
    let expected = [1, 5, 11];
    for x in a.difference(&b) {
        assert!(expected.contains(x));
        i += 1
    }
    assert_eq!(i, expected.len());
}

#[test]
fn test_symmetric_difference() {
    let mut a = HashSet::new();
    let mut b = HashSet::new();

    assert!(a.insert(1));
    assert!(a.insert(3));
    assert!(a.insert(5));
    assert!(a.insert(9));
    assert!(a.insert(11));

    assert!(b.insert(-2));
    assert!(b.insert(3));
    assert!(b.insert(9));
    assert!(b.insert(14));
    assert!(b.insert(22));

    let mut i = 0;
    let expected = [-2, 1, 5, 11, 14, 22];
    for x in a.symmetric_difference(&b) {
        assert!(expected.contains(x));
        i += 1
    }
    assert_eq!(i, expected.len());
}

#[test]
fn test_union() {
    let mut a = HashSet::new();
    let mut b = HashSet::new();
    assert!(a.union(&b).next().is_none());
    assert!(b.union(&a).next().is_none());

    assert!(a.insert(1));
    assert!(a.insert(3));
    assert!(a.insert(11));
    assert!(a.insert(16));
    assert!(a.insert(19));
    assert!(a.insert(24));

    assert!(b.insert(-2));
    assert!(b.insert(1));
    assert!(b.insert(5));
    assert!(b.insert(9));
    assert!(b.insert(13));
    assert!(b.insert(19));

    let mut i = 0;
    let expected = [-2, 1, 3, 5, 9, 11, 13, 16, 19, 24];
    for x in a.union(&b) {
        assert!(expected.contains(x));
        i += 1
    }
    assert_eq!(i, expected.len());

    assert!(a.insert(9)); // make a bigger than b
    assert!(a.insert(5));

    i = 0;
    for x in a.union(&b) {
        assert!(expected.contains(x));
        i += 1
    }
    assert_eq!(i, expected.len());

    i = 0;
    for x in b.union(&a) {
        assert!(expected.contains(x));
        i += 1
    }
    assert_eq!(i, expected.len());
}

#[test]
fn test_from_iter() {
    let xs = [1, 2, 2, 3, 4, 5, 6, 7, 8, 9];

    let set: HashSet<_> = xs.iter().cloned().collect();

    for x in &xs {
        assert!(set.contains(x));
    }

    assert_eq!(set.iter().len(), xs.len() - 1);
}

#[test]
fn test_move_iter() {
    let hs = {
        let mut hs = HashSet::new();

        hs.insert('a');
        hs.insert('b');

        hs
    };

    let v = hs.into_iter().collect::<Vec<char>>();
    assert!(v == ['a', 'b'] || v == ['b', 'a']);
}

#[test]
fn test_eq() {
    // These constants once happened to expose a bug in insert().
    // I'm keeping them around to prevent a regression.
    let mut s1 = HashSet::new();

    s1.insert(1);
    s1.insert(2);
    s1.insert(3);

    let mut s2 = HashSet::new();

    s2.insert(1);
    s2.insert(2);

    assert!(s1 != s2);

    s2.insert(3);

    assert_eq!(s1, s2);
}

#[test]
fn test_show() {
    let mut set = HashSet::new();
    let empty = HashSet::<i32>::new();

    set.insert(1);
    set.insert(2);

    let set_str = format!("{set:?}");

    assert!(set_str == "{1, 2}" || set_str == "{2, 1}");
    assert_eq!(format!("{empty:?}"), "{}");
}

#[test]
fn test_trivial_drain() {
    let mut s = HashSet::<i32>::new();
    for _ in s.drain() {}
    assert!(s.is_empty());
    drop(s);

    let mut s = HashSet::<i32>::new();
    drop(s.drain());
    assert!(s.is_empty());
}

#[test]
fn test_drain() {
    let mut s: HashSet<_> = (1..100).collect();

    // try this a bunch of times to make sure we don't screw up internal state.
    for _ in 0..20 {
        assert_eq!(s.len(), 99);

        {
            let mut last_i = 0;
            let mut d = s.drain();
            for (i, x) in d.by_ref().take(50).enumerate() {
                last_i = i;
                assert!(x != 0);
            }
            assert_eq!(last_i, 49);
        }

        for _ in &s {
            panic!("s should be empty!");
        }

        // reset to try again.
        s.extend(1..100);
    }
}

#[test]
fn test_replace() {
    use crate::hash;

    #[derive(Debug)]
    struct Foo(&'static str, #[allow(dead_code)] i32);

    impl PartialEq for Foo {
        fn eq(&self, other: &Self) -> bool {
            self.0 == other.0
        }
    }

    impl Eq for Foo {}

    impl hash::Hash for Foo {
        fn hash<H: hash::Hasher>(&self, h: &mut H) {
            self.0.hash(h);
        }
    }

    let mut s = HashSet::new();
    assert_eq!(s.replace(Foo("a", 1)), None);
    assert_eq!(s.len(), 1);
    assert_eq!(s.replace(Foo("a", 2)), Some(Foo("a", 1)));
    assert_eq!(s.len(), 1);

    let mut it = s.iter();
    assert_eq!(it.next(), Some(&Foo("a", 2)));
    assert_eq!(it.next(), None);
}

#[test]
fn test_extend_ref() {
    let mut a = HashSet::new();
    a.insert(1);

    a.extend(&[2, 3, 4]);

    assert_eq!(a.len(), 4);
    assert!(a.contains(&1));
    assert!(a.contains(&2));
    assert!(a.contains(&3));
    assert!(a.contains(&4));

    let mut b = HashSet::new();
    b.insert(5);
    b.insert(6);

    a.extend(&b);

    assert_eq!(a.len(), 6);
    assert!(a.contains(&1));
    assert!(a.contains(&2));
    assert!(a.contains(&3));
    assert!(a.contains(&4));
    assert!(a.contains(&5));
    assert!(a.contains(&6));
}

#[test]
fn test_retain() {
    let xs = [1, 2, 3, 4, 5, 6];
    let mut set: HashSet<i32> = xs.iter().cloned().collect();
    set.retain(|&k| k % 2 == 0);
    assert_eq!(set.len(), 3);
    assert!(set.contains(&2));
    assert!(set.contains(&4));
    assert!(set.contains(&6));
}

#[test]
fn test_extract_if_empty() {
    let mut set: HashSet<i32> = HashSet::new();
    let extracted: Vec<_> =
        set.extract_if(|_| unreachable!("there's nothing to decide on")).collect();

    assert!(extracted.is_empty());
    assert!(set.is_empty());
}

#[test]
fn test_extract_if_consuming_nothing() {
    let mut set: HashSet<_> = (0..3).collect();
    let extracted: Vec<_> = set.extract_if(|_| false).collect();

    assert!(extracted.is_empty());
    assert_eq!(set, HashSet::from([0, 1, 2]));
}

#[test]
fn test_extract_if_consuming_all() {
    let mut set: HashSet<_> = (0..3).collect();
    let mut extracted: Vec<_> = set.extract_if(|_| true).collect();
    extracted.sort_unstable();

    assert_eq!(extracted, vec![0, 1, 2]);
    assert!(set.is_empty());
}

#[test]
#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
fn test_extract_if_drop_panic_leak() {
    static PREDS: AtomicU32 = AtomicU32::new(0);
    static DROPS: AtomicU32 = AtomicU32::new(0);

    #[derive(PartialEq, Eq, PartialOrd, Hash)]
    struct D(i32);
    impl Drop for D {
        fn drop(&mut self) {
            if DROPS.fetch_add(1, Ordering::SeqCst) == 1 {
                panic!("panic in `drop`");
            }
        }
    }

    let mut set = (0..3).map(|i| D(i)).collect::<HashSet<_>>();

    catch_unwind(move || {
        set.extract_if(|_| {
            PREDS.fetch_add(1, Ordering::SeqCst);
            true
        })
        .for_each(drop)
    })
    .ok();

    assert_eq!(PREDS.load(Ordering::SeqCst), 2);
    assert_eq!(DROPS.load(Ordering::SeqCst), 3);
}

#[test]
#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
fn test_extract_if_pred_panic_leak() {
    static PREDS: AtomicU32 = AtomicU32::new(0);
    static DROPS: AtomicU32 = AtomicU32::new(0);

    #[derive(PartialEq, Eq, PartialOrd, Hash)]
    struct D;
    impl Drop for D {
        fn drop(&mut self) {
            DROPS.fetch_add(1, Ordering::SeqCst);
        }
    }

    let mut set: HashSet<_> = (0..3).map(|_| D).collect();

    catch_unwind(AssertUnwindSafe(|| {
        set.extract_if(|_| match PREDS.fetch_add(1, Ordering::SeqCst) {
            0 => true,
            _ => panic!(),
        })
        .for_each(drop)
    }))
    .ok();

    assert_eq!(PREDS.load(Ordering::SeqCst), 1);
    assert_eq!(DROPS.load(Ordering::SeqCst), 3);
    assert_eq!(set.len(), 0);
}

#[test]
fn from_array() {
    let set = HashSet::from([1, 2, 3, 4]);
    let unordered_duplicates = HashSet::from([4, 1, 4, 3, 2]);
    assert_eq!(set, unordered_duplicates);

    // This next line must infer the hasher type parameter.
    // If you make a change that causes this line to no longer infer,
    // that's a problem!
    let _must_not_require_type_annotation = HashSet::from([1, 2]);
}

#[test]
fn const_with_hasher() {
    const X: HashSet<(), ()> = HashSet::with_hasher(());
    const Y: HashSet<(), ()> = Default::default();
    assert_eq!(X.len(), 0);
    assert_eq!(Y.len(), 0);
}

#[test]
fn test_insert_does_not_overwrite_the_value() {
    let first_value = Arc::new(17);
    let second_value = Arc::new(17);

    let mut set = HashSet::new();
    let inserted = set.insert(first_value.clone());
    assert!(inserted);

    let inserted = set.insert(second_value);
    assert!(!inserted);

    assert!(
        Arc::ptr_eq(set.iter().next().unwrap(), &first_value),
        "Insert must not overwrite the value, so the contained value pointer \
            must be the same as first value pointer we inserted"
    );
}