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feat(core): settle the Store trait (flush, is_empty, conformance suite)

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kyle
2026-10-22 08:44:09 -07:00
parent 158689e265
commit 07907efec5
13 changed files with 416 additions and 40 deletions
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tines-core/src/store_conformance.rs
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//! Backend conformance suite.
//!
//! A `no_std`-clean set of property tests that any [`Store`] backend can run to
//! prove it honors the contract in [`Store`](crate::Store). Each public function
//! exercises exactly one property against a backend produced by a
//! caller-supplied factory, so the same body runs for [`MemStore`], a
//! [`LogStore`](crate::store::LogStore) opened on a fresh file per case and
//! [`CappedStore`] — see the `#[test]` shims in each backend crate.
//!
//! The functions build their own [`Observation`]s, including one carrying a
//! `sig`, which only the crate that owns the `#[non_exhaustive]` type may
//! construct by struct literal — this is why the suite lives *inside*
//! `tines-core` rather than as a `tines-core/tests/` file.
//!
//! The suite is deliberately free of `std`/`alloc` so it can build under
//! `--no-default-features` (with this feature on): every call is `heapless`
//! plus `assert!`.
use crate::observation::Observation;
use crate::{Payload, SigAlgo, Signature, Store, Topic, TrimPolicy};
/// Build a signed broadcast observation for the suite.
///
/// `signature` is a byte string the backend need not understand; the test only
/// checks it round-trips verbatim, so it is any length `<= MAX_SIG`.
fn signed_obs(seq: u64, topic: &[u8], signature: &[u8]) -> Observation {
let payload = Payload::from_slice(b"pay").expect("payload fits capacity");
Observation {
observer: [1u8; 16],
seq,
age_ms: 0,
observed_at: None,
topic: Topic::from_slice(topic).expect("topic fits capacity"),
payload,
dest: None,
sig: Some(Signature {
version: 1,
algo: SigAlgo::Ed25519,
bytes: heapless::Vec::from_slice(signature).expect("signature fits capacity"),
}),
}
}
/// Two observations that carry the *same* id: same content, different age.
/// The signature is ignored by identity, so an aged copy reuses the id.
fn same_id(seq: u64, topic: &[u8]) -> (Observation, Observation) {
let fresh = signed_obs(seq, topic, &[0u8; 8]);
let mut aged = signed_obs(seq, topic, &[0u8; 8]);
aged.age_ms = 500;
(fresh, aged)
}
/// A freshly inserted observation must be retrievable by id at `now`.
pub fn insert_get<S: Store>(mut make: impl FnMut() -> S) {
let mut store = make();
let (obs, _) = same_id(1, b"t");
let id = obs.id();
assert!(store.insert(obs, 1000).unwrap(), "insert succeeds");
let got = store.get(&id, 1000).expect("get after insert");
assert_eq!(got.seq, 1);
assert_eq!(got.topic.as_slice(), b"t");
assert_eq!(got.payload.as_slice(), b"pay");
}
/// A second insert of an already-held id is a no-op: the entry, its stored age
/// lineage and its release state are left untouched.
pub fn dedupe<S: Store>(mut make: impl FnMut() -> S) {
let mut store = make();
assert!(store.is_empty());
let (fresh, aged) = same_id(1, b"t");
let id = fresh.id();
assert_eq!(id, aged.id(), "an aged copy shares the id");
assert!(store.insert(fresh, 1000).unwrap(), "first insert");
assert_eq!(store.len(), 1);
assert!(
!store.insert(aged, 1500).unwrap(),
"duplicate is not reinserted"
);
assert_eq!(store.len(), 1);
assert!(store.contains(&id));
}
/// `get` advances age by elapsed ticks; a deduped insert must not reset the
/// stored age lineage.
pub fn age_lineage<S: Store>(mut make: impl FnMut() -> S) {
let mut store = make();
let (fresh, _) = same_id(1, b"t");
let id = fresh.id();
store.insert(fresh, 1000).unwrap();
let first = store.get(&id, 1500).unwrap();
assert_eq!(first.age_ms, 500, "age advances to elapsed ticks");
// A later insert of the same id must not reset stored_at.
store.insert(same_id(1, b"t").0, 3000).unwrap();
let second = store.get(&id, 3500).unwrap();
assert_eq!(
second.age_ms, 2500,
"age keeps climbing from the first insert, not the duplicate"
);
}
/// `get` with `now` before the stored tick saturates to zero age — it must not
/// underflow.
pub fn saturating_ticks<S: Store>(mut make: impl FnMut() -> S) {
let mut store = make();
let (fresh, _) = same_id(1, b"t");
let id = fresh.id();
store.insert(fresh, 2000).unwrap();
let got = store.get(&id, 1000).unwrap();
assert_eq!(got.age_ms, 0, "elapsed underflow saturates at zero");
}
/// Releasing marks an id but leaves it stored, contained and gettable; it must
/// not evict the entry.
pub fn release_surviving_get<S: Store>(mut make: impl FnMut() -> S) {
let mut store = make();
let (fresh, _) = same_id(1, b"t");
let id = fresh.id();
store.insert(fresh, 1000).unwrap();
store.release(&id);
assert!(store.is_released(&id));
assert!(store.contains(&id), "release does not evict");
assert!(
store.get(&id, 1000).is_some(),
"released id is still gettable"
);
assert_eq!(store.len(), 1);
}
/// A signature carried by an observation round-trips through the store intact,
/// and a different signature over the same content shares the id.
pub fn sig_round_trip<S: Store>(mut make: impl FnMut() -> S) {
let mut store = make();
let sig_bytes = [7u8; 32];
let fresh = signed_obs(1, b"sig", &sig_bytes);
let id = fresh.id();
store.insert(fresh, 1000).unwrap();
let got = store.get(&id, 1000).unwrap();
let sig = got
.sig
.expect("the signature round-trips through the store");
assert_eq!(sig.version, 1);
assert_eq!(sig.algo, SigAlgo::Ed25519);
assert_eq!(&sig.bytes[..], &sig_bytes[..]);
// A different signature over identical content must not change identity.
let other = signed_obs(1, b"sig", &[9u8; 40]);
assert_eq!(other.id(), id, "the signature must not affect identity");
}
/// With a count cap, `trim` drops the oldest (highest current age) first and
/// reports how many it removed.
pub fn trim_order<S: Store>(mut make: impl FnMut() -> S) {
let mut store = make();
for i in 0..5u64 {
let fresh = signed_obs(i, b"t", &[i as u8]);
assert!(store.insert(fresh, i * 10).unwrap(), "insert {}", i);
}
let policy = TrimPolicy {
keep_per_topic: None,
max_age_ms: None,
max_count: Some(2),
};
assert_eq!(
store.trim(&policy, 50),
3,
"trim returns the number removed"
);
// The two youngest (seq 3 and 4, lowest current age) survive.
for dropped in 0..3u64 {
let fresh = signed_obs(dropped, b"t", &[dropped as u8]);
assert!(!store.contains(&fresh.id()), "seq {} is trimmed", dropped);
}
for kept in 3..5u64 {
let fresh = signed_obs(kept, b"t", &[kept as u8]);
assert!(store.contains(&fresh.id()), "seq {} survives", kept);
}
}
/// A trimmed id is not tombstoned: it can be reinserted and counted again.
pub fn no_tombstones<S: Store>(mut make: impl FnMut() -> S) {
let mut store = make();
let fresh = signed_obs(1, b"t", &[1u8; 8]);
let id = fresh.id();
store.insert(fresh, 0).unwrap();
let policy = TrimPolicy {
keep_per_topic: None,
max_age_ms: Some(1),
max_count: None,
};
assert_eq!(store.trim(&policy, 100), 1);
assert!(store.is_empty());
// The trimmed id is not tombstoned: re-insert it (aged, still same id).
let reinserted = signed_obs(1, b"t", &[1u8; 8]);
let mut reinserted = reinserted;
reinserted.age_ms = 5;
assert_eq!(reinserted.id(), id, "an aged re-insert keeps the id");
assert!(
store.insert(reinserted, 0).unwrap(),
"a trimmed id can be reinserted"
);
assert!(store.contains(&id));
assert_eq!(store.len(), 1);
}
/// Flushing twice is safe: it must not error and must not evict, and age must
/// keep advancing afterwards.
pub fn idempotent_flush<S: Store>(mut make: impl FnMut() -> S) {
let mut store = make();
let fresh = signed_obs(1, b"t", &[1u8; 8]);
let id = fresh.id();
store.insert(fresh, 1000).unwrap();
assert!(
store.flush(2000).is_ok(),
"the first flush is a best-effort success"
);
assert!(
store.flush(2000).is_ok(),
"the second flush is a no-op that still succeeds"
);
assert!(store.contains(&id), "flush does not evict");
assert_eq!(store.len(), 1);
let got = store.get(&id, 2500).unwrap();
assert_eq!(got.age_ms, 1500, "age keeps advancing past a flush");
}