diff --git a/tests-lib/helper.js b/tests-lib/helper.js
index 4a2d6376..dbbefbdc 100644
--- a/tests-lib/helper.js
+++ b/tests-lib/helper.js
@@ -133,7 +133,7 @@ export async function initArrays (t, opts) {
   var result = {
     users: []
   }
-  var share = Object.assign({ flushHelper: 'Map', array: 'Array' }, opts.share)
+  var share = Object.assign({ flushHelper: 'Map', array: 'Array', map: 'Map' }, opts.share)
   var chance = opts.chance || new Chance(t.getSeed() * 1000000000)
   var connector = Object.assign({ room: 'debugging_' + t.name, generateUserId: false, testContext: t, chance }, opts.connector)
   for (let i = 0; i < opts.users; i++) {