diff --git a/src/test/java/org/elasticsearch/test/InternalTestCluster.java b/src/test/java/org/elasticsearch/test/InternalTestCluster.java
index 4fcc4dd3a16..57b72ee84c7 100644
--- a/src/test/java/org/elasticsearch/test/InternalTestCluster.java
+++ b/src/test/java/org/elasticsearch/test/InternalTestCluster.java
@@ -74,6 +74,7 @@ import org.elasticsearch.index.cache.filter.AutoFilterCachingPolicy;
 import org.elasticsearch.index.cache.filter.FilterCacheModule;
 import org.elasticsearch.index.cache.filter.none.NoneFilterCache;
 import org.elasticsearch.index.cache.filter.weighted.WeightedFilterCache;
+import org.elasticsearch.index.engine.EngineModule;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.indices.IndicesService;
 import org.elasticsearch.indices.breaker.CircuitBreakerService;
@@ -88,6 +89,7 @@ import org.elasticsearch.search.SearchService;
 import org.elasticsearch.test.cache.recycler.MockBigArraysModule;
 import org.elasticsearch.test.cache.recycler.MockPageCacheRecyclerModule;
 import org.elasticsearch.test.disruption.ServiceDisruptionScheme;
+import org.elasticsearch.test.engine.MockEngineModule;
 import org.elasticsearch.test.store.MockFSIndexStoreModule;
 import org.elasticsearch.test.transport.AssertingLocalTransport;
 import org.elasticsearch.test.transport.MockTransportService;
@@ -362,6 +364,8 @@ public final class InternalTestCluster extends TestCluster {
                 .put(SETTING_CLUSTER_NODE_SEED, seed);
         if (ENABLE_MOCK_MODULES && usually(random)) {
             builder.put("index.store.type", MockFSIndexStoreModule.class.getName()); // no RAM dir for now!
+            builder.put(EngineModule.ENGINE_TYPE, MockEngineModule.class.getName());
+
             builder.put(PageCacheRecyclerModule.CACHE_IMPL, MockPageCacheRecyclerModule.class.getName());
             builder.put(BigArraysModule.IMPL, MockBigArraysModule.class.getName());
             builder.put(TransportModule.TRANSPORT_SERVICE_TYPE_KEY, MockTransportService.class.getName());