diff --git a/beacon_node/http_api/tests/common.rs b/beacon_node/http_api/tests/common.rs
index f7d30c9e0..fba1671c6 100644
--- a/beacon_node/http_api/tests/common.rs
+++ b/beacon_node/http_api/tests/common.rs
@@ -1,5 +1,8 @@
 use beacon_chain::{
-    test_utils::{BeaconChainHarness, BoxedMutator, EphemeralTestingSlotClockHarnessType},
+    test_utils::{
+        BeaconChainHarness, BoxedMutator, Builder,
+        EphemeralTestingSlotClockHarnessType as HarnessType,
+    },
     BeaconChain, BeaconChainTypes,
 };
 use directory::DEFAULT_ROOT_DIR;
@@ -38,7 +41,7 @@ pub const EXTERNAL_ADDR: &str = "/ip4/0.0.0.0/tcp/9000";
 
 /// HTTP API tester that allows interaction with the underlying beacon chain harness.
 pub struct InteractiveTester<E: EthSpec> {
-    pub harness: BeaconChainHarness<EphemeralTestingSlotClockHarnessType<E>>,
+    pub harness: BeaconChainHarness<HarnessType<E>>,
     pub client: BeaconNodeHttpClient,
     pub network_rx: NetworkReceivers<E>,
     _server_shutdown: oneshot::Sender<()>,
@@ -56,9 +59,8 @@ pub struct ApiServer<E: EthSpec, SFut: Future<Output = ()>> {
     pub external_peer_id: PeerId,
 }
 
-type Initializer<E> = Box<
-    dyn FnOnce(HarnessBuilder<EphemeralHarnessType<E>>) -> HarnessBuilder<EphemeralHarnessType<E>>,
->;
+type HarnessBuilder<E> = Builder<HarnessType<E>, TestingSlotClock>;
+type Initializer<E> = Box<dyn FnOnce(HarnessBuilder<E>) -> HarnessBuilder<E>>;
 type Mutator<E> = BoxedMutator<E, MemoryStore<E>, MemoryStore<E>, TestingSlotClock>;
 
 impl<E: EthSpec> InteractiveTester<E> {