Extend BeaconChain persistence testing

beacon_node/beacon_chain/src/fork_choice.rs

@@ -35,6 +35,16 @@ pub struct ForkChoice<T: BeaconChainTypes> {
     best_justified_checkpoint: RwLock<Checkpoint>,
 }
 
+impl<T: BeaconChainTypes> PartialEq for ForkChoice<T> {
+    /// This implementation ignores the `store`.
+    fn eq(&self, other: &Self) -> bool {
+        self.backend == other.backend
+            && self.genesis_block_root == other.genesis_block_root
+            && *self.justified_checkpoint.read() == *other.justified_checkpoint.read()
+            && *self.best_justified_checkpoint.read() == *other.best_justified_checkpoint.read()
+    }
+}
+
 impl<T: BeaconChainTypes> ForkChoice<T> {
     /// Instantiate a new fork chooser.
     ///

beacon_node/beacon_chain/tests/persistence_tests.rs

@@ -3,7 +3,10 @@
 #[macro_use]
 extern crate lazy_static;
 
-use beacon_chain::test_utils::{AttestationStrategy, BeaconChainHarness, BlockStrategy};
+use beacon_chain::{
+    test_utils::{AttestationStrategy, BeaconChainHarness, BlockStrategy},
+    BeaconChain, BeaconChainTypes,
+};
 use sloggers::{null::NullLoggerBuilder, Build};
 use std::sync::Arc;
 use store::DiskStore;
@@ -55,15 +58,7 @@ fn finalizes_after_resuming_from_db() {
 
     let latest_slot = harness.chain.slot().expect("should have a slot");
 
-    let original_head = harness.chain.head();
+    harness.chain.persist().expect("should persist the chain");
-    let original_heads = harness.chain.heads();
-
-    assert_eq!(
-        original_head.beacon_state.slot, first_half,
-        "head should be half way through test"
-    );
-
-    drop(harness);
 
     let resumed_harness = BeaconChainHarness::resume_from_disk_store(
         MinimalEthSpec,
@@ -71,6 +66,14 @@ fn finalizes_after_resuming_from_db() {
         KEYPAIRS[0..validator_count].to_vec(),
     );
 
+    assert_chains_pretty_much_the_same(&harness.chain, &resumed_harness.chain);
+
+    // Ensures we don't accidentally use it again.
+    //
+    // Note: this will persist the chain again, but that shouldn't matter since nothing has
+    // changed.
+    drop(harness);
+
     // Set the slot clock of the resumed harness to be in the slot following the previous harness.
     //
     // This allows us to produce the block at the next slot.
@@ -79,18 +82,6 @@ fn finalizes_after_resuming_from_db() {
         .slot_clock
         .set_slot(latest_slot.as_u64() + 1);
 
-    assert_eq!(
-        original_head,
-        resumed_harness.chain.head(),
-        "resumed head should be same as previous head"
-    );
-
-    assert_eq!(
-        original_heads,
-        resumed_harness.chain.heads(),
-        "resumed heads should be same as previous heads"
-    );
-
     resumed_harness.extend_chain(
         (num_blocks_produced - first_half) as usize,
         BlockStrategy::OnCanonicalHead,
@@ -118,3 +109,18 @@ fn finalizes_after_resuming_from_db() {
         "the head should be finalized two behind the current epoch"
     );
 }
+
+fn assert_chains_pretty_much_the_same<T: BeaconChainTypes>(a: &BeaconChain<T>, b: &BeaconChain<T>) {
+    assert_eq!(a.spec, b.spec, "spec should be equal");
+    assert_eq!(a.op_pool, b.op_pool, "op_pool should be equal");
+    assert_eq!(a.head(), b.head(), "head() should be equal");
+    assert_eq!(a.heads(), b.heads(), "heads() should be equal");
+    assert_eq!(
+        a.genesis_block_root, b.genesis_block_root,
+        "genesis_block_root should be equal"
+    );
+    assert!(
+        a.fork_choice == b.fork_choice,
+        "fork_choice should be equal"
+    );
+}

eth2/lmd_ghost/src/lib.rs

@@ -8,7 +8,9 @@ pub use reduced_tree::ThreadSafeReducedTree;
 
 pub type Result<T> = std::result::Result<T, String>;
 
-pub trait LmdGhost<S: Store, E: EthSpec>: Send + Sync + Sized {
+// Note: the `PartialEq` bound is only required for testing. If it becomes a serious annoyance we
+// can remove it.
+pub trait LmdGhost<S: Store, E: EthSpec>: PartialEq + Send + Sync + Sized {
     /// Create a new instance, with the given `store` and `finalized_root`.
     fn new(store: Arc<S>, finalized_block: &BeaconBlock<E>, finalized_root: Hash256) -> Self;
 

eth2/lmd_ghost/src/reduced_tree.rs

@@ -55,6 +55,13 @@ impl<T, E> fmt::Debug for ThreadSafeReducedTree<T, E> {
     }
 }
 
+impl<T, E> PartialEq for ThreadSafeReducedTree<T, E> {
+    /// This implementation ignores the `store`.
+    fn eq(&self, other: &Self) -> bool {
+        *self.core.read() == *other.core.read()
+    }
+}
+
 impl<T, E> LmdGhost<T, E> for ThreadSafeReducedTree<T, E>
 where
     T: Store,
@@ -200,6 +207,15 @@ impl<T, E> fmt::Debug for ReducedTree<T, E> {
     }
 }
 
+impl<T, E> PartialEq for ReducedTree<T, E> {
+    /// This implementation ignores the `store` field.
+    fn eq(&self, other: &Self) -> bool {
+        self.nodes == other.nodes
+            && self.latest_votes == other.latest_votes
+            && self.root == other.root
+    }
+}
+
 impl<T, E> ReducedTree<T, E>
 where
     T: Store,
@@ -918,7 +934,7 @@ pub struct Vote {
 ///
 /// E.g., a `get` or `insert` to an out-of-bounds element will cause the Vec to grow (using
 /// Default) to the smallest size required to fulfill the request.
-#[derive(Default, Clone, Debug)]
+#[derive(Default, Clone, Debug, PartialEq)]
 pub struct ElasticList<T>(Vec<T>);
 
 impl<T> ElasticList<T>

tests/beacon_chain_sim/src/main.rs

@@ -1,3 +1,5 @@
+// mod simulated_network;
+
 use node_test_rig::{
     environment::{Environment, EnvironmentBuilder, RuntimeContext},
     testing_client_config, ClientConfig, ClientGenesis, LocalBeaconNode, LocalValidatorClient,
@@ -7,6 +9,7 @@ use std::time::{SystemTime, UNIX_EPOCH};
 use types::EthSpec;
 
 pub type BeaconNode<E> = LocalBeaconNode<ProductionClient<E>>;
+pub type ValidatorClient<E> = LocalValidatorClient<E>;
 
 fn main() {
     let nodes = 4;