Generalize sync block lookup tests (#6498)

* Generalize sync block lookup tests

beacon_node/network/src/sync/tests/mod.rs

@@ -0,0 +1,67 @@
+use crate::sync::manager::SyncManager;
+use crate::sync::range_sync::RangeSyncType;
+use crate::sync::SyncMessage;
+use crate::NetworkMessage;
+use beacon_chain::builder::Witness;
+use beacon_chain::eth1_chain::CachingEth1Backend;
+use beacon_chain::test_utils::{BeaconChainHarness, EphemeralHarnessType};
+use beacon_processor::WorkEvent;
+use lighthouse_network::NetworkGlobals;
+use slog::Logger;
+use slot_clock::ManualSlotClock;
+use std::sync::Arc;
+use store::MemoryStore;
+use tokio::sync::mpsc;
+use types::{test_utils::XorShiftRng, ForkName, MinimalEthSpec as E};
+
+mod lookups;
+mod range;
+
+type T = Witness<ManualSlotClock, CachingEth1Backend<E>, E, MemoryStore<E>, MemoryStore<E>>;
+
+/// This test utility enables integration testing of Lighthouse sync components.
+///
+/// It covers the following:
+/// 1. Sending `SyncMessage` to `SyncManager` to trigger `RangeSync`, `BackFillSync` and `BlockLookups` behaviours.
+/// 2. Making assertions on `WorkEvent`s received from sync
+/// 3. Making assertion on `NetworkMessage` received from sync (Outgoing RPC requests).
+///
+/// The test utility covers testing the interactions from and to `SyncManager`. In diagram form:
+///                      +-----------------+
+///                      | BeaconProcessor |
+///                      +---------+-------+
+///                             ^  |
+///                             |  |
+///                   WorkEvent |  | SyncMsg
+///                             |  | (Result)
+///                             |  v
+/// +--------+            +-----+-----------+             +----------------+
+/// | Router +----------->|  SyncManager    +------------>| NetworkService |
+/// +--------+  SyncMsg   +-----------------+ NetworkMsg  +----------------+
+///           (RPC resp)  |  - RangeSync    |  (RPC req)
+///                       +-----------------+
+///                       |  - BackFillSync |
+///                       +-----------------+
+///                       |  - BlockLookups |
+///                       +-----------------+
+struct TestRig {
+    /// Receiver for `BeaconProcessor` events (e.g. block processing results).
+    beacon_processor_rx: mpsc::Receiver<WorkEvent<E>>,
+    beacon_processor_rx_queue: Vec<WorkEvent<E>>,
+    /// Receiver for `NetworkMessage` (e.g. outgoing RPC requests from sync)
+    network_rx: mpsc::UnboundedReceiver<NetworkMessage<E>>,
+    /// Stores all `NetworkMessage`s received from `network_recv`. (e.g. outgoing RPC requests)
+    network_rx_queue: Vec<NetworkMessage<E>>,
+    /// Receiver for `SyncMessage` from the network
+    sync_rx: mpsc::UnboundedReceiver<SyncMessage<E>>,
+    /// To send `SyncMessage`. For sending RPC responses or block processing results to sync.
+    sync_manager: SyncManager<T>,
+    /// To manipulate sync state and peer connection status
+    network_globals: Arc<NetworkGlobals<E>>,
+    /// Beacon chain harness
+    harness: BeaconChainHarness<EphemeralHarnessType<E>>,
+    /// `rng` for generating test blocks and blobs.
+    rng: XorShiftRng,
+    fork_name: ForkName,
+    log: Logger,
+}