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//! Sanity check that alternate hashers work correctly.
#![cfg(not(miri))] // FIXME: takes too long
use hashbrown::HashSet;
use std::hash::{BuildHasher, BuildHasherDefault, Hasher};
fn check<S: BuildHasher + Default>() {
let range = 0..1_000;
let mut set = HashSet::<i32, S>::default();
set.extend(range.clone());
assert!(!set.contains(&i32::min_value()));
assert!(!set.contains(&(range.start - 1)));
for i in range.clone() {
assert!(set.contains(&i));
}
assert!(!set.contains(&range.end));
assert!(!set.contains(&i32::max_value()));
}
/// Use hashbrown's default hasher.
#[test]
fn default() {
check::<hashbrown::hash_map::DefaultHashBuilder>();
}
/// Use std's default hasher.
#[test]
fn random_state() {
check::<std::collections::hash_map::RandomState>();
}
/// Use a constant 0 hash.
#[test]
fn zero() {
#[derive(Default)]
struct ZeroHasher;
impl Hasher for ZeroHasher {
fn finish(&self) -> u64 {
0
}
fn write(&mut self, _: &[u8]) {}
}
check::<BuildHasherDefault<ZeroHasher>>();
}
/// Use a constant maximum hash.
#[test]
fn max() {
#[derive(Default)]
struct MaxHasher;
impl Hasher for MaxHasher {
fn finish(&self) -> u64 {
u64::max_value()
}
fn write(&mut self, _: &[u8]) {}
}
check::<BuildHasherDefault<MaxHasher>>();
}