quickchecks.rs - mozsearch

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extern crate seahash;

#[macro_use]

extern crate quickcheck;

use quickcheck::TestResult;

use seahash::hash;

use seahash::reference::hash as reference;

use seahash::SeaHasher;

use std::hash::Hasher;

use std::num::{NonZeroU8, NonZeroUsize};

quickcheck! {

    #[cfg_attr(miri, ignore)] // very slow to run on miri

    fn chunked_matches_buffered(xs: Vec<u8>, chunk_size: NonZeroUsize, times: NonZeroU8, additional: u8) -> TestResult {

        let target_size = xs.len() * times.get() as usize + additional as usize;

        if xs.is_empty() || target_size > 10_000_000 {

            TestResult::discard()

        } else {

            let xs = xs.into_iter()

                .cycle()

                // the vecs produced by quickcheck are perhaps a bit small by default.

                // additional should add some noise to avoid only getting nice even lengths.

                .take(target_size)

                .collect::<Vec<_>>();

            // write all at once

            let mut h0 = SeaHasher::default();

            h0.write(&xs);

            let h0 = h0.finish();

            // write in chunks

            let mut h1 = SeaHasher::default();

            for chunk in xs.chunks(chunk_size.get()) {

                h1.write(chunk);

            let h1 = h1.finish();

            // compare all, including to buffered and reference

            let outcome = h0 == h1

                && h0 == hash(&xs)

                && h0 == reference(&xs);

            TestResult::from_bool(outcome)