private StorageEngine callGetStorageEngine(Config config, SystemStreamPartition changelogSSP) {
    when(this.jobContext.getConfig()).thenReturn(config);
    return new MockKeyValueStorageEngineFactory(this.rawKeyValueStore).getStorageEngine(STORE_NAME, this.storeDir,
        this.keySerde, this.msgSerde, this.changelogCollector, this.metricsRegistry, changelogSSP, this.jobContext,
        this.containerContext, STORE_MODE);
  }
@param changelogSSP if non-null, then enables logged store
samza-kv/src/test/java/org/apache/samza/storage/kv/TestBaseKeyValueStorageEngineFactory.java