diff --git a/modules/store/testing/src/mock_reducer_manager.ts b/modules/store/testing/src/mock_reducer_manager.ts
index 2cfc7ba8f9..b7fc1f6bb9 100644
--- a/modules/store/testing/src/mock_reducer_manager.ts
+++ b/modules/store/testing/src/mock_reducer_manager.ts
@@ -9,4 +9,12 @@ export class MockReducerManager extends BehaviorSubject<
   constructor() {
     super(() => undefined);
   }
+  
+  addFeature(feature: any) {
+    /* noop */
+  }
+
+  addFeatures(feature: any) {
+    /* noop */
+  }
 }