Refactor BeaconStateBuilder

Made it a production-only struct. All the testing stuff can be done with
BeaconStateBencher

beacon_node/beacon_chain/test_harness/src/beacon_chain_harness.rs

@@ -1,6 +1,7 @@
 use super::ValidatorHarness;
 use beacon_chain::{BeaconChain, BlockProcessingOutcome};
 pub use beacon_chain::{BeaconChainError, CheckPoint};
+use bls::get_withdrawal_credentials;
 use db::{
     stores::{BeaconBlockStore, BeaconStateStore},
     MemoryDB,
@@ -43,7 +44,12 @@ impl BeaconChainHarness {
     ///
     /// - A keypair, `BlockProducer` and `Attester` for each validator.
     /// - A new BeaconChain struct where the given validators are in the genesis.
-    pub fn new(spec: ChainSpec, validator_count: usize, validators_dir: Option<&Path>) -> Self {
+    pub fn new(
+        spec: ChainSpec,
+        validator_count: usize,
+        validators_dir: Option<&Path>,
+        skip_deposit_verification: bool,
+    ) -> Self {
         let db = Arc::new(MemoryDB::open());
         let block_store = Arc::new(BeaconBlockStore::new(db.clone()));
         let state_store = Arc::new(BeaconStateStore::new(db.clone()));
@@ -57,22 +63,47 @@ impl BeaconChainHarness {
 
         let mut state_builder = BeaconStateBuilder::new(genesis_time, latest_eth1_data, &spec);
 
-        // If a `validators_dir` is specified, load the keypairs and validators from YAML files.
+        // If a `validators_dir` is specified, load the keypairs a YAML file.
         //
-        // Otherwise, build all the keypairs and initial validator deposits manually.
-        //
-        // It is _much_ faster to load from YAML, however it does skip all the initial processing
-        // and verification of `Deposits`, so it is a slightly less comprehensive test.
+        // Otherwise, generate them deterministically where the first validator has a secret key of
+        // `1`, etc.
         let keypairs = if let Some(path) = validators_dir {
             debug!("Loading validator keypairs from file...");
             let keypairs_file = File::open(path.join("keypairs.yaml")).unwrap();
             let mut keypairs: Vec<Keypair> = serde_yaml::from_reader(&keypairs_file).unwrap();
             keypairs.truncate(validator_count);
+            keypairs
+        } else {
+            debug!("Generating validator keypairs...");
+            generate_deterministic_keypairs(validator_count)
+        };
 
-            debug!("Loading validators from file...");
-            let validators_file = File::open(path.join("validators.yaml")).unwrap();
-            let mut validators: Vec<Validator> = serde_yaml::from_reader(&validators_file).unwrap();
-            validators.truncate(validator_count);
+        // Skipping deposit verification means directly generating `Validator` records, instead
+        // of generating `Deposit` objects, verifying them and converting them into `Validator`
+        // records.
+        //
+        // It is much faster to skip deposit verification, however it does not test the initial
+        // validator induction part of beacon chain genesis.
+        if skip_deposit_verification {
+            let validators = keypairs
+                .iter()
+                .map(|keypair| {
+                    let withdrawal_credentials = Hash256::from_slice(&get_withdrawal_credentials(
+                        &keypair.pk,
+                        spec.bls_withdrawal_prefix_byte,
+                    ));
+
+                    Validator {
+                        pubkey: keypair.pk.clone(),
+                        withdrawal_credentials,
+                        activation_epoch: spec.far_future_epoch,
+                        exit_epoch: spec.far_future_epoch,
+                        withdrawable_epoch: spec.far_future_epoch,
+                        initiated_exit: false,
+                        slashed: false,
+                    }
+                })
+                .collect();
 
             let balances = vec![32_000_000_000; validator_count];
 
@@ -82,15 +113,10 @@ impl BeaconChainHarness {
                 validator_count as u64,
                 &spec,
             );
-
-            keypairs
         } else {
-            debug!("Generating validator keypairs...");
-            let keypairs = generate_deterministic_keypairs(validator_count);
             debug!("Generating initial validator deposits...");
             let deposits = generate_deposits_from_keypairs(&keypairs, genesis_time, &spec);
             state_builder.process_initial_deposits(&deposits, &spec);
-            keypairs
         };
 
         let genesis_state = state_builder.build(&spec).unwrap();

beacon_node/beacon_chain/test_harness/src/test_case.rs

@@ -81,7 +81,7 @@ impl TestCase {
             validator_count
         );
 
-        let mut harness = BeaconChainHarness::new(spec, validator_count, validators_dir);
+        let mut harness = BeaconChainHarness::new(spec, validator_count, validators_dir, true);
 
         info!("Starting simulation across {} slots...", slots);