diff --git a/polkadot/node/subsystem-bench/src/lib/approval/mod.rs b/polkadot/node/subsystem-bench/src/lib/approval/mod.rs
index 5c0c65b11cdb..b033be9986f4 100644
--- a/polkadot/node/subsystem-bench/src/lib/approval/mod.rs
+++ b/polkadot/node/subsystem-bench/src/lib/approval/mod.rs
@@ -60,7 +60,7 @@ use polkadot_node_subsystem_util::metrics::Metrics;
 use polkadot_overseer::Handle as OverseerHandleReal;
 use polkadot_primitives::{
 	BlockNumber, CandidateEvent, CandidateIndex, CandidateReceipt, Hash, Header, Slot,
-	ValidatorIndex,
+	ValidatorIndex, ASSIGNMENT_KEY_TYPE_ID,
 };
 use prometheus::Registry;
 use sc_keystore::LocalKeystore;
@@ -68,6 +68,7 @@ use sc_service::SpawnTaskHandle;
 use serde::{Deserialize, Serialize};
 use sp_consensus_babe::Epoch as BabeEpoch;
 use sp_core::H256;
+use sp_keystore::Keystore;
 use std::{
 	cmp::max,
 	collections::{HashMap, HashSet},
@@ -785,6 +786,12 @@ fn build_overseer(
 	let db: polkadot_node_subsystem_util::database::kvdb_impl::DbAdapter<kvdb_memorydb::InMemory> =
 		polkadot_node_subsystem_util::database::kvdb_impl::DbAdapter::new(db, &[]);
 	let keystore = LocalKeystore::in_memory();
+	keystore
+		.sr25519_generate_new(
+			ASSIGNMENT_KEY_TYPE_ID,
+			Some(state.test_authorities.key_seeds.get(NODE_UNDER_TEST as usize).unwrap().as_str()),
+		)
+		.unwrap();
 
 	let system_clock =
 		PastSystemClock::new(SystemClock {}, state.delta_tick_from_generated.clone());
diff --git a/polkadot/node/subsystem-bench/src/lib/mock/runtime_api.rs b/polkadot/node/subsystem-bench/src/lib/mock/runtime_api.rs
index be9dbd55cb6f..ee45ea05c925 100644
--- a/polkadot/node/subsystem-bench/src/lib/mock/runtime_api.rs
+++ b/polkadot/node/subsystem-bench/src/lib/mock/runtime_api.rs
@@ -28,7 +28,7 @@ use polkadot_node_subsystem_types::OverseerSignal;
 use polkadot_primitives::{
 	node_features, AsyncBackingParams, CandidateEvent, CandidateReceipt, CoreState, GroupIndex,
 	GroupRotationInfo, IndexedVec, NodeFeatures, OccupiedCore, ScheduledCore, SessionIndex,
-	SessionInfo, ValidatorIndex,
+	SessionInfo, ValidationCode, ValidatorIndex,
 };
 use sp_consensus_babe::Epoch as BabeEpoch;
 use sp_core::H256;
@@ -288,6 +288,15 @@ impl MockRuntimeApi {
 							};
 							tx.send(Ok((groups, group_rotation_info))).unwrap();
 						},
+						RuntimeApiMessage::Request(
+							_parent,
+							RuntimeApiRequest::ValidationCodeByHash(_, tx),
+						) => {
+							let validation_code = ValidationCode(Vec::new());
+							if let Err(err) = tx.send(Ok(Some(validation_code))) {
+								gum::error!(target: LOG_TARGET, ?err, "validation code wasn't received");
+							}
+						},
 						// Long term TODO: implement more as needed.
 						message => {
 							unimplemented!("Unexpected runtime-api message: {:?}", message)