diff --git a/beacon_node/beacon_chain/src/beacon_chain.rs b/beacon_node/beacon_chain/src/beacon_chain.rs
index 9e3f6b52c..8602d32c7 100644
--- a/beacon_node/beacon_chain/src/beacon_chain.rs
+++ b/beacon_node/beacon_chain/src/beacon_chain.rs
@@ -88,6 +88,8 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         genesis_block: BeaconBlock,
         spec: ChainSpec,
     ) -> Result<Self, Error> {
+        genesis_state.build_all_caches(&spec)?;
+
         let state_root = genesis_state.canonical_root();
         store.put(&state_root, &genesis_state)?;
 
@@ -105,8 +107,6 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
             state_root,
         ));
 
-        genesis_state.build_all_caches(&spec)?;
-
         Ok(Self {
             spec,
             slot_clock,
diff --git a/beacon_node/beacon_chain/src/lib.rs b/beacon_node/beacon_chain/src/lib.rs
index 4aa1370d9..67b0cee47 100644
--- a/beacon_node/beacon_chain/src/lib.rs
+++ b/beacon_node/beacon_chain/src/lib.rs
@@ -5,6 +5,7 @@ mod fork_choice;
 pub mod iter;
 mod metrics;
 mod persisted_beacon_chain;
+mod test_utils;
 
 pub use self::beacon_chain::{BeaconChain, BeaconChainTypes, BlockProcessingOutcome};
 pub use self::checkpoint::CheckPoint;
diff --git a/beacon_node/beacon_chain/src/test_utils.rs b/beacon_node/beacon_chain/src/test_utils.rs
new file mode 100644
index 000000000..be370ff65
--- /dev/null
+++ b/beacon_node/beacon_chain/src/test_utils.rs
@@ -0,0 +1,147 @@
+use crate::{BeaconChain, BeaconChainTypes, BlockProcessingOutcome};
+use lmd_ghost::{LmdGhost, ThreadSafeReducedTree};
+use slot_clock::SlotClock;
+use slot_clock::TestingSlotClock;
+use std::marker::PhantomData;
+use std::sync::Arc;
+use store::MemoryStore;
+use tree_hash::{SignedRoot, TreeHash};
+use types::{
+    test_utils::TestingBeaconStateBuilder, BeaconBlock, ChainSpec, Domain, EthSpec, Hash256,
+    Keypair, MinimalEthSpec, Signature,
+};
+
+pub struct CommonTypes<L, E>
+where
+    L: LmdGhost<MemoryStore, E>,
+    E: EthSpec,
+{
+    _phantom_l: PhantomData<L>,
+    _phantom_e: PhantomData<E>,
+}
+
+impl<L, E> BeaconChainTypes for CommonTypes<L, E>
+where
+    L: LmdGhost<MemoryStore, E>,
+    E: EthSpec,
+{
+    type Store = MemoryStore;
+    type SlotClock = TestingSlotClock;
+    type LmdGhost = L;
+    type EthSpec = E;
+}
+
+pub struct BeaconChainHarness<L, E>
+where
+    L: LmdGhost<MemoryStore, E>,
+    E: EthSpec,
+{
+    chain: BeaconChain<CommonTypes<L, E>>,
+    keypairs: Vec<Keypair>,
+    spec: ChainSpec,
+}
+
+impl<L, E> BeaconChainHarness<L, E>
+where
+    L: LmdGhost<MemoryStore, E>,
+    E: EthSpec,
+{
+    pub fn new(validator_count: usize) -> Self {
+        let spec = E::default_spec();
+
+        let store = Arc::new(MemoryStore::open());
+
+        let state_builder =
+            TestingBeaconStateBuilder::from_default_keypairs_file_if_exists(validator_count, &spec);
+        let (genesis_state, keypairs) = state_builder.build();
+
+        let mut genesis_block = BeaconBlock::empty(&spec);
+        genesis_block.state_root = Hash256::from_slice(&genesis_state.tree_hash_root());
+
+        // Slot clock
+        let slot_clock = TestingSlotClock::new(
+            spec.genesis_slot,
+            genesis_state.genesis_time,
+            spec.seconds_per_slot,
+        );
+
+        let chain = BeaconChain::from_genesis(
+            store,
+            slot_clock,
+            genesis_state,
+            genesis_block,
+            spec.clone(),
+        )
+        .expect("Terminate if beacon chain generation fails");
+
+        Self {
+            chain,
+            keypairs,
+            spec,
+        }
+    }
+
+    pub fn extend_canonical_chain(&self) {
+        self.chain.slot_clock.advance_slot();
+        self.chain.catchup_state().expect("should catchup state");
+
+        let block = self.build_block();
+        let outcome = self
+            .chain
+            .process_block(block)
+            .expect("should process block");
+        assert_eq!(outcome, BlockProcessingOutcome::Processed);
+    }
+
+    fn build_block(&self) -> BeaconBlock {
+        let slot = self.chain.read_slot_clock().unwrap();
+
+        let sk = {
+            let proposer = self
+                .chain
+                .block_proposer(slot)
+                .expect("should get block propoer");
+            &self.keypairs[proposer].sk
+        };
+
+        let fork = &self.chain.head().beacon_state.fork;
+
+        let randao_reveal = {
+            let epoch = slot.epoch(E::slots_per_epoch());
+            let message = epoch.tree_hash_root();
+            let domain = self.spec.get_domain(epoch, Domain::Randao, fork);
+            Signature::new(&message, domain, sk)
+        };
+
+        let (mut block, _state) = self
+            .chain
+            .produce_block(randao_reveal)
+            .expect("should producer block");
+
+        block.signature = {
+            let message = block.signed_root();
+            let epoch = block.slot.epoch(E::slots_per_epoch());
+            let domain = self.spec.get_domain(epoch, Domain::BeaconProposer, fork);
+            Signature::new(&message, domain, sk)
+        };
+
+        block
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    pub const VALIDATOR_COUNT: usize = 16;
+
+    #[test]
+    fn build_on_genesis() {
+        let harness: BeaconChainHarness<
+            ThreadSafeReducedTree<MemoryStore, MinimalEthSpec>,
+            MinimalEthSpec,
+        > = BeaconChainHarness::new(VALIDATOR_COUNT);
+
+        harness.extend_canonical_chain();
+    }
+}
diff --git a/eth2/utils/slot_clock/src/testing_slot_clock.rs b/eth2/utils/slot_clock/src/testing_slot_clock.rs
index fc9b7201b..ab00d2baa 100644
--- a/eth2/utils/slot_clock/src/testing_slot_clock.rs
+++ b/eth2/utils/slot_clock/src/testing_slot_clock.rs
@@ -15,6 +15,10 @@ impl TestingSlotClock {
     pub fn set_slot(&self, slot: u64) {
         *self.slot.write().expect("TestingSlotClock poisoned.") = Slot::from(slot);
     }
+
+    pub fn advance_slot(&self) {
+        self.set_slot(self.present_slot().unwrap().unwrap().as_u64() + 1)
+    }
 }
 
 impl SlotClock for TestingSlotClock {