chia_query/peer/light_client/

provider.rs

//! [`LightClientProvider`] — a synchronous [`ChainSource`] facade over the light client's
//! subscription cache + a pooled wallet-protocol session.
//!
//! Reads answer from the local [`CoinStateCache`](super::cache::CoinStateCache) first; a miss falls
//! through to a **non-subscribing** peer query (so a read never silently grows the subscription
//! set). Every outcome honours the interface's fail-closed contract: `Ok(None)`/empty means the
//! peer reliably reported absence, while any transport/subscription-gap failure is an `Err` — NEVER
//! a false `Ok(None)`.
//!
//! ## Boundary
//!
//! A subscribing light client is not a full archival index. Two reads are deliberately reported as
//! [`ChainSourceError::Unsupported`] rather than answered unreliably:
//! - [`resolve_singleton_lineage`](ChainSource::resolve_singleton_lineage) — a money-critical
//!   forward walk better served by an aggregating source; answering it from subscription state
//!   would risk a spoofable, partial lineage.
//! - [`block_timestamp`](ChainSource::block_timestamp) — a light source keeps no timestamp index.
//!
//! The registry composes providers, so these fall through to a source that does support them.
//!
//! ## The provider descriptor is EARNED, not asserted
//!
//! `chia-peer` derived this provider's [`ProviderKind`] from a config flag — whether the operator
//! had *named* an endpoint — with no way to check that the peer actually answering was the one
//! named. A co-resident or `config.endpoint` peer therefore outranked coinset.org at priority 20
//! with nothing able to tell it apart from an anonymous introducer result.
//!
//! Pooled, the answering session carries a
//! [`PeerOrigin`](crate::peer::connect::PeerOrigin), so the descriptor is built from what the pool
//! OBSERVED rather than from what the operator declared — see
//! [`ChiaLightClient::as_chain_source_provider`](super::ChiaLightClient::as_chain_source_provider).

use std::sync::Arc;

use chia_protocol::{Bytes32, CoinSpend, CoinState, CoinStateFilters, Program};
use dig_chainsource_interface::{
    ChainSource, ChainSourceError, ChainSourceProvider, CoinRecord, ProviderInfo, SingletonLineage,
};
use tokio::runtime::Handle;
use tokio::sync::RwLock;

use super::cache::CoinStateCache;
use super::fetcher::CoinStateFetcher;
use crate::provider_registry::bridge::run_blocking;

/// A [`ChainSource`] provider backed by a subscribing Chia light client.
///
/// Cloning shares the underlying cache, fetcher, and runtime handle.
#[derive(Clone)]
pub struct LightClientProvider {
    fetcher: Arc<dyn CoinStateFetcher>,
    cache: Arc<RwLock<CoinStateCache>>,
    handle: Handle,
    info: ProviderInfo,
}

impl LightClientProvider {
    /// Builds a provider reading through `fetcher` + `cache`, driving async reads on `handle` (which
    /// MUST belong to a multi-thread runtime — see the crate's async→sync bridge), described by
    /// `info`.
    pub fn new(
        fetcher: Arc<dyn CoinStateFetcher>,
        cache: Arc<RwLock<CoinStateCache>>,
        handle: Handle,
        info: ProviderInfo,
    ) -> Self {
        Self {
            fetcher,
            cache,
            handle,
            info,
        }
    }

    /// Resolves a coin's current state: cache first, then a non-subscribing peer read.
    fn coin_state(&self, coin_id: Bytes32) -> Result<Option<CoinState>, ChainSourceError> {
        let fetcher = self.fetcher.clone();
        let cache = self.cache.clone();
        run_blocking(&self.handle, async move {
            if let Some(cached) = cache.read().await.get(coin_id) {
                return Ok(Some(cached));
            }
            let states = fetcher.coin_states(vec![coin_id], false).await?;
            Ok::<_, super::error::LightClientError>(
                states.into_iter().find(|s| s.coin.coin_id() == coin_id),
            )
        })?
        .map_err(ChainSourceError::from)
    }
}

impl ChainSource for LightClientProvider {
    type Error = ChainSourceError;

    fn coin_record(&self, coin_id: Bytes32) -> Result<Option<CoinRecord>, Self::Error> {
        let peak = self.peak_height()?;
        Ok(self
            .coin_state(coin_id)?
            .map(CoinRecord::from_coin_state)
            .map(|record| clamp_record_heights_to_peak(record, peak)))
    }

    fn coin_records_by_puzzle_hash(
        &self,
        puzzle_hash: Bytes32,
        include_spent: bool,
    ) -> Result<Vec<CoinRecord>, Self::Error> {
        let fetcher = self.fetcher.clone();
        let filters = CoinStateFilters {
            include_spent,
            include_unspent: true,
            include_hinted: true,
            min_amount: 0,
        };
        let states = run_blocking(&self.handle, async move {
            fetcher
                .puzzle_states(vec![puzzle_hash], filters, false)
                .await
        })?
        .map_err(ChainSourceError::from)?;
        let peak = self.peak_height()?;
        Ok(states
            .into_iter()
            .map(CoinRecord::from_coin_state)
            .map(|record| clamp_record_heights_to_peak(record, peak))
            .collect())
    }

    fn coin_records_by_parent(
        &self,
        parent_coin_id: Bytes32,
    ) -> Result<Vec<CoinRecord>, Self::Error> {
        let fetcher = self.fetcher.clone();
        let states = run_blocking(&self.handle, async move {
            fetcher.children(parent_coin_id).await
        })?
        .map_err(ChainSourceError::from)?;
        let peak = self.peak_height()?;
        Ok(states
            .into_iter()
            .map(CoinRecord::from_coin_state)
            .map(|record| clamp_record_heights_to_peak(record, peak))
            .collect())
    }

    fn coin_spend(&self, coin_id: Bytes32) -> Result<Option<CoinSpend>, Self::Error> {
        // The spend that spent `coin_id` exists only once the coin has a spent height; the coin
        // itself supplies the real puzzle hash the CoinSpend needs (never a placeholder).
        let Some(state) = self.coin_state(coin_id)? else {
            return Ok(None);
        };
        let Some(spent_height) = state.spent_height else {
            return Ok(None);
        };
        let fetcher = self.fetcher.clone();
        let (puzzle, solution) = run_blocking(&self.handle, async move {
            fetcher.puzzle_and_solution(coin_id, spent_height).await
        })?
        .map_err(ChainSourceError::from)?;

        // Defend against a lying peer: the reveal MUST hash to the coin's own puzzle hash, else the
        // spend is not this coin's. Fail closed on a mismatch or an unparseable reveal.
        verify_reveal_matches(&puzzle, state.coin.puzzle_hash)?;
        Ok(Some(CoinSpend::new(state.coin, puzzle, solution)))
    }

    fn resolve_singleton_lineage(
        &self,
        _launcher_id: Bytes32,
    ) -> Result<Option<SingletonLineage>, Self::Error> {
        Err(ChainSourceError::Unsupported(
            "singleton lineage resolution is not provided by the light-client source; \
             use an aggregating chain source",
        ))
    }

    fn peak_height(&self) -> Result<Option<u32>, Self::Error> {
        let cache = self.cache.clone();
        let peak = run_blocking(&self.handle, async move { cache.read().await.peak() })?;
        Ok(peak.map(|(height, _)| height))
    }

    fn block_timestamp(&self, _height: u32) -> Result<Option<u64>, Self::Error> {
        Err(ChainSourceError::Unsupported(
            "block timestamps are not indexed by the light-client source",
        ))
    }
}

impl ChainSourceProvider for LightClientProvider {
    fn provider_info(&self) -> ProviderInfo {
        self.info.clone()
    }
}

/// Bounds a record's reported block heights (`confirmed_height` and `spent_height`) by the current
/// known peak.
///
/// The cache read path already upholds "no coin has a height `> peak_height`" structurally (see
/// [`CoinStateCache`](super::cache::CoinStateCache)), but the cache-MISS *live-fetch* path surfaces
/// the peer's heights directly. A coin created or spent in the current tip block — read in the
/// one-block window before the drive loop processes the matching `NewPeakWallet` — would otherwise
/// report a height `> peak_height`, underflowing a consumer's `peak_height - height` (u32) depth count
/// (confirmations for `confirmed_height`, spend-depth for `spent_height`) into a spurious ~4.29-billion
/// value on a money path.
///
/// Clamping each height to `min(height, peak)` makes such a coin report 0 confirmations / 0 spend-depth
/// — the conservative, understating direction — while keeping it PRESENT (never omitted) and keeping
/// `spent_height` `Some` (the coin IS spent; only the reported HEIGHT is clamped, never the
/// spent-vs-unspent flag). The peak is left untouched (a lying peer must not be able to inflate it via
/// a fetched coin). When no peak is known yet, `peak_height` is `None`, so no `peak - height`
/// subtraction is possible and the heights are left as reported.
fn clamp_record_heights_to_peak(mut record: CoinRecord, peak: Option<u32>) -> CoinRecord {
    let Some(peak) = peak else { return record };
    if let Some(confirmed) = record.confirmed_height {
        record.confirmed_height = Some(confirmed.min(peak));
    }
    if let Some(spent) = record.spent_height {
        record.spent_height = Some(spent.min(peak));
    }
    record
}

/// Verifies a puzzle reveal hashes to `expected` (the coin's own puzzle hash), failing closed on a
/// mismatch or an unparseable reveal. A lying peer cannot pass off a wrong reveal as this coin's.
fn verify_reveal_matches(puzzle: &Program, expected: Bytes32) -> Result<(), ChainSourceError> {
    let actual: Bytes32 = chia_wallet_sdk::clvm_utils::tree_hash_from_bytes(puzzle.as_ref())
        .map_err(|e| ChainSourceError::Malformed(format!("undecodable puzzle reveal: {e}")))?
        .into();
    if actual != expected {
        return Err(ChainSourceError::Malformed(
            "puzzle reveal does not hash to the coin's puzzle hash".into(),
        ));
    }
    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::peer::light_client::error::LightClientError;
    use async_trait::async_trait;
    use chia_protocol::{Coin, Program};
    use dig_chainsource_interface::{ProviderId, ProviderKind};
    use std::borrow::Cow;

    /// A scripted fetcher: each read returns the configured `Ok(..)` states or a forced error, so
    /// the provider's fail-closed mapping can be exercised without a live node.
    #[derive(Default, Clone)]
    struct MockFetcher {
        coin_states: Vec<CoinState>,
        fail: Option<LightClientError>,
        children: Vec<CoinState>,
        puzzle_states: Vec<CoinState>,
        reveal: Option<(Program, Program)>,
    }

    #[async_trait]
    impl CoinStateFetcher for MockFetcher {
        async fn coin_states(
            &self,
            _coin_ids: Vec<Bytes32>,
            _subscribe: bool,
        ) -> Result<Vec<CoinState>, LightClientError> {
            match &self.fail {
                Some(e) => Err(e.clone()),
                None => Ok(self.coin_states.clone()),
            }
        }
        async fn puzzle_states(
            &self,
            _puzzle_hashes: Vec<Bytes32>,
            _filters: CoinStateFilters,
            _subscribe: bool,
        ) -> Result<Vec<CoinState>, LightClientError> {
            match &self.fail {
                Some(e) => Err(e.clone()),
                None => Ok(self.puzzle_states.clone()),
            }
        }
        async fn children(&self, _coin_id: Bytes32) -> Result<Vec<CoinState>, LightClientError> {
            match &self.fail {
                Some(e) => Err(e.clone()),
                None => Ok(self.children.clone()),
            }
        }
        async fn puzzle_and_solution(
            &self,
            _coin_id: Bytes32,
            _height: u32,
        ) -> Result<(Program, Program), LightClientError> {
            if let Some(e) = &self.fail {
                return Err(e.clone());
            }
            match &self.reveal {
                Some(reveal) => Ok(reveal.clone()),
                // Absence is impossible on this path (caller confirmed spent) → fail closed.
                None => Err(LightClientError::Rejected("no reveal".into())),
            }
        }
    }

    /// A puzzle reveal and the coin puzzle hash it hashes to, so `coin_spend`'s reveal verification
    /// passes for a legitimately-served spend.
    fn reveal_and_matching_puzzle_hash() -> (Program, Bytes32) {
        let puzzle = Program::from(vec![1u8]);
        let ph: Bytes32 = chia_wallet_sdk::clvm_utils::tree_hash_from_bytes(puzzle.as_ref())
            .unwrap()
            .into();
        (puzzle, ph)
    }

    fn info() -> ProviderInfo {
        ProviderInfo {
            id: ProviderId(Cow::Borrowed("chia-query-light-client-test")),
            kind: ProviderKind::Custom,
            priority: 20,
            trustless: false,
        }
    }

    fn provider_with(fetcher: MockFetcher) -> (tokio::runtime::Runtime, LightClientProvider) {
        provider_with_peak(fetcher, None)
    }

    /// Builds a provider whose cache has been advanced to `peak` (if any), so the live-fetch clamp
    /// against the known peak can be exercised.
    fn provider_with_peak(
        fetcher: MockFetcher,
        peak: Option<u32>,
    ) -> (tokio::runtime::Runtime, LightClientProvider) {
        let rt = tokio::runtime::Builder::new_multi_thread()
            .worker_threads(1)
            .enable_all()
            .build()
            .expect("multi-thread runtime");
        let mut cache = CoinStateCache::new();
        if let Some(height) = peak {
            cache.set_peak(height, Bytes32::new([0xAB; 32]));
        }
        let provider = LightClientProvider::new(
            Arc::new(fetcher),
            Arc::new(RwLock::new(cache)),
            rt.handle().clone(),
            info(),
        );
        (rt, provider)
    }

    /// Runs the sync facade method off any ambient runtime (bridge's "outside a runtime" path).
    fn call<T: Send>(f: impl FnOnce() -> T + Send) -> T {
        std::thread::scope(|s| s.spawn(f).join().expect("thread panicked"))
    }

    fn coin(seed: u8) -> Coin {
        Coin::new(Bytes32::new([seed; 32]), Bytes32::new([seed ^ 1; 32]), 1)
    }

    // ---- Test #1: the fail-closed crux ----

    #[test]
    fn coin_record_returns_some_for_a_known_coin() {
        let c = coin(7);
        let id = c.coin_id();
        let fetcher = MockFetcher {
            coin_states: vec![CoinState {
                coin: c,
                created_height: Some(100),
                spent_height: None,
            }],
            ..Default::default()
        };
        let (_rt, provider) = provider_with(fetcher);
        let record = call(move || provider.coin_record(id)).expect("read ok");
        assert!(record.is_some());
        assert_eq!(record.unwrap().confirmed_height, Some(100));
    }

    /// #1326 regression: a cache-miss live fetch returning a coin created ABOVE the current peak (the
    /// one-block window before the matching NewPeakWallet lands) must report `confirmed_height`
    /// clamped to the peak (0 confirmations), NEVER above it — and the coin must stay PRESENT, not
    /// omitted, since it genuinely exists.
    #[test]
    fn live_fetched_coin_above_peak_reports_clamped_confirmed_height() {
        let c = coin(11);
        let id = c.coin_id();
        let fetcher = MockFetcher {
            coin_states: vec![CoinState {
                coin: c,
                created_height: Some(1_000_001), // above the peak below
                spent_height: None,
            }],
            ..Default::default()
        };
        let (_rt, provider) = provider_with_peak(fetcher, Some(1_000_000));
        let record = call(move || provider.coin_record(id))
            .expect("read ok")
            .expect("coin present, never omitted");
        assert_eq!(
            record.confirmed_height,
            Some(1_000_000),
            "an above-peak live coin must clamp to the peak (0 confirmations), never overstate"
        );
    }

    /// A live-fetched coin created at/below the peak keeps its real confirmation height (the clamp is
    /// a no-op on the normal path).
    #[test]
    fn live_fetched_coin_at_or_below_peak_is_unaffected() {
        let c = coin(12);
        let id = c.coin_id();
        let fetcher = MockFetcher {
            coin_states: vec![CoinState {
                coin: c,
                created_height: Some(900_000),
                spent_height: None,
            }],
            ..Default::default()
        };
        let (_rt, provider) = provider_with_peak(fetcher, Some(1_000_000));
        let record = call(move || provider.coin_record(id))
            .expect("read ok")
            .expect("coin present");
        assert_eq!(record.confirmed_height, Some(900_000));
    }

    /// The same clamp holds on the discovery read paths, which are always live (never cache-first).
    #[test]
    fn discovery_reads_clamp_above_peak_confirmed_height() {
        let fetcher = MockFetcher {
            puzzle_states: vec![CoinState {
                coin: coin(13),
                created_height: Some(2_000_000),
                spent_height: Some(2_000_000),
            }],
            children: vec![CoinState {
                coin: coin(14),
                created_height: Some(2_000_000),
                spent_height: Some(2_000_000),
            }],
            ..Default::default()
        };
        let (_rt, provider) = provider_with_peak(fetcher, Some(1_000_000));
        let ph = Bytes32::new([8; 32]);
        let parent = Bytes32::new([9; 32]);
        let p = provider.clone();
        let by_ph = call(move || p.coin_records_by_puzzle_hash(ph, true)).unwrap();
        assert_eq!(by_ph[0].confirmed_height, Some(1_000_000));
        assert_eq!(by_ph[0].spent_height, Some(1_000_000));
        let by_parent = call(move || provider.coin_records_by_parent(parent)).unwrap();
        assert_eq!(by_parent[0].confirmed_height, Some(1_000_000));
        assert_eq!(by_parent[0].spent_height, Some(1_000_000));
    }

    /// #1346 regression (symmetric to #1326): a cache-miss live fetch returning a coin SPENT above
    /// the current peak (the one-block window before the matching NewPeakWallet lands) must report
    /// `spent_height` clamped to the peak (0 spend-depth), NEVER above it — closing the identical
    /// `peak_height - spent_height` (u32) underflow. The coin stays PRESENT and stays marked SPENT
    /// (`spent_height` remains `Some`); only the reported height is clamped.
    #[test]
    fn live_fetched_coin_spent_above_peak_reports_clamped_spent_height() {
        let c = coin(15);
        let id = c.coin_id();
        let fetcher = MockFetcher {
            coin_states: vec![CoinState {
                coin: c,
                created_height: Some(999_999),
                spent_height: Some(1_000_001), // spent above the peak below
            }],
            ..Default::default()
        };
        let (_rt, provider) = provider_with_peak(fetcher, Some(1_000_000));
        let record = call(move || provider.coin_record(id))
            .expect("read ok")
            .expect("coin present, never omitted");
        assert_eq!(
            record.spent_height,
            Some(1_000_000),
            "an above-peak spent coin must clamp spent_height to the peak (0 spend-depth), never overstate"
        );
        assert!(
            record.is_spent(),
            "the coin IS spent — clamping the reported height must never drop the spent flag"
        );
    }

    /// A live-fetched coin spent at/below the peak keeps its real spend height (the clamp is a no-op
    /// on the normal path).
    #[test]
    fn live_fetched_coin_spent_at_or_below_peak_is_unaffected() {
        let c = coin(16);
        let id = c.coin_id();
        let fetcher = MockFetcher {
            coin_states: vec![CoinState {
                coin: c,
                created_height: Some(800_000),
                spent_height: Some(900_000),
            }],
            ..Default::default()
        };
        let (_rt, provider) = provider_with_peak(fetcher, Some(1_000_000));
        let record = call(move || provider.coin_record(id))
            .expect("read ok")
            .expect("coin present");
        assert_eq!(record.spent_height, Some(900_000));
    }

    /// The clamp must not flip a spent coin to unspent: `coin_spend` keys spentness on the RAW peer
    /// state (not the clamped record), so a coin spent above the lagged peak still assembles its spend.
    #[test]
    fn coin_spend_of_coin_spent_above_peak_still_identified_as_spent() {
        let (puzzle, ph) = reveal_and_matching_puzzle_hash();
        let c = Coin::new(Bytes32::new([17; 32]), ph, 1);
        let id = c.coin_id();
        let fetcher = MockFetcher {
            coin_states: vec![CoinState {
                coin: c,
                created_height: Some(999_999),
                spent_height: Some(1_000_001), // above the peak
            }],
            reveal: Some((puzzle, Program::from(vec![2u8]))),
            ..Default::default()
        };
        let (_rt, provider) = provider_with_peak(fetcher, Some(1_000_000));
        let spend = call(move || provider.coin_spend(id))
            .unwrap()
            .expect("a coin spent above the lagged peak is still spent");
        assert_eq!(spend.coin, c);
    }

    #[test]
    fn coin_record_returns_none_for_provable_absence() {
        let (_rt, provider) = provider_with(MockFetcher::default());
        let id = coin(9).coin_id();
        let record = call(move || provider.coin_record(id)).expect("read ok");
        assert_eq!(record, None);
    }

    #[test]
    fn transport_failure_is_err_never_false_absence() {
        let fetcher = MockFetcher {
            fail: Some(LightClientError::Transport("socket reset".into())),
            ..Default::default()
        };
        let (_rt, provider) = provider_with(fetcher);
        let id = coin(3).coin_id();
        let result = call(move || provider.coin_record(id));
        assert!(
            matches!(result, Err(ChainSourceError::Transport(_))),
            "a transport failure MUST be Err, never Ok(None): {result:?}"
        );
    }

    #[test]
    fn coin_spend_of_unspent_coin_is_none() {
        let c = coin(4);
        let id = c.coin_id();
        let fetcher = MockFetcher {
            coin_states: vec![CoinState {
                coin: c,
                created_height: Some(10),
                spent_height: None,
            }],
            ..Default::default()
        };
        let (_rt, provider) = provider_with(fetcher);
        assert_eq!(call(move || provider.coin_spend(id)).unwrap(), None);
    }

    #[test]
    fn coin_spend_of_spent_coin_assembles_from_real_coin() {
        let (puzzle, ph) = reveal_and_matching_puzzle_hash();
        let c = Coin::new(Bytes32::new([5; 32]), ph, 1);
        let id = c.coin_id();
        let fetcher = MockFetcher {
            coin_states: vec![CoinState {
                coin: c,
                created_height: Some(10),
                spent_height: Some(20),
            }],
            reveal: Some((puzzle, Program::from(vec![2u8]))),
            ..Default::default()
        };
        let (_rt, provider) = provider_with(fetcher);
        let spend = call(move || provider.coin_spend(id))
            .unwrap()
            .expect("spend");
        assert_eq!(spend.coin, c);
    }

    /// Fix 3 regression: a KNOWN-SPENT coin whose reveal the peer rejects must fail closed with
    /// `Err` — NEVER `Ok(None)` (which would corrupt the interface's parent-walk authentication).
    #[test]
    fn coin_spend_of_spent_coin_with_rejected_reveal_is_err_never_none() {
        let c = coin(6);
        let id = c.coin_id();
        let fetcher = MockFetcher {
            coin_states: vec![CoinState {
                coin: c,
                created_height: Some(10),
                spent_height: Some(20),
            }],
            reveal: None, // peer rejects / has no reveal
            ..Default::default()
        };
        let (_rt, provider) = provider_with(fetcher);
        let result = call(move || provider.coin_spend(id));
        assert!(
            matches!(result, Err(ChainSourceError::Transport(_))),
            "a rejected reveal for a spent coin must be Err, never Ok(None): {result:?}"
        );
    }

    /// Fix 4 regression: a reveal that does NOT hash to the coin's puzzle hash (a lying peer) is
    /// rejected as malformed, never assembled into a bogus spend.
    #[test]
    fn coin_spend_rejects_a_reveal_that_does_not_hash_to_the_coin() {
        let c = coin(8); // puzzle_hash is [8^1;32], which the reveal below will NOT hash to
        let id = c.coin_id();
        let fetcher = MockFetcher {
            coin_states: vec![CoinState {
                coin: c,
                created_height: Some(10),
                spent_height: Some(20),
            }],
            reveal: Some((Program::from(vec![1u8]), Program::from(vec![2u8]))),
            ..Default::default()
        };
        let (_rt, provider) = provider_with(fetcher);
        let result = call(move || provider.coin_spend(id));
        assert!(
            matches!(result, Err(ChainSourceError::Malformed(_))),
            "a mismatched reveal must be Malformed: {result:?}"
        );
    }

    #[test]
    fn records_by_puzzle_hash_and_parent_map_states() {
        let fetcher = MockFetcher {
            puzzle_states: vec![CoinState {
                coin: coin(1),
                created_height: Some(1),
                spent_height: None,
            }],
            children: vec![CoinState {
                coin: coin(2),
                created_height: Some(2),
                spent_height: None,
            }],
            ..Default::default()
        };
        let (_rt, provider) = provider_with(fetcher);
        let ph = Bytes32::new([8; 32]);
        let parent = Bytes32::new([9; 32]);
        let p = provider.clone();
        assert_eq!(
            call(move || p.coin_records_by_puzzle_hash(ph, true))
                .unwrap()
                .len(),
            1
        );
        assert_eq!(
            call(move || provider.coin_records_by_parent(parent))
                .unwrap()
                .len(),
            1
        );
    }

    #[test]
    fn lineage_and_timestamp_are_unsupported_not_false_absence() {
        let (_rt, provider) = provider_with(MockFetcher::default());
        let p = provider.clone();
        assert!(matches!(
            call(move || p.resolve_singleton_lineage(Bytes32::new([1; 32]))),
            Err(ChainSourceError::Unsupported(_))
        ));
        assert!(matches!(
            call(move || provider.block_timestamp(1)),
            Err(ChainSourceError::Unsupported(_))
        ));
    }

    #[test]
    fn provider_info_is_reported() {
        let (_rt, provider) = provider_with(MockFetcher::default());
        assert_eq!(provider.provider_info().priority, 20);
        assert_eq!(provider.peak_height().unwrap(), None);
    }
}