diff --git a/bin/utils.js b/bin/utils.js
index ea76c8c..8e93413 100644
--- a/bin/utils.js
+++ b/bin/utils.js
@@ -25,6 +25,14 @@ if (typeof persistenceDir === 'string') {
   persistence = new LevelDbPersistence(persistenceDir)
 }
 
+/**
+ * @param {{bindState: function(string,WSSharedDoc):void,
+ * writeState:function(string,WSSharedDoc):Promise}|null} persistence_
+ */
+export const setPersistence = persistence_ => {
+  persistence = persistence_
+}
+
 /**
  * @type {Map<string,WSSharedDoc>}
  */