diff --git a/lib/galaxy/app_unittest_utils/galaxy_mock.py b/lib/galaxy/app_unittest_utils/galaxy_mock.py
index 696b1441d7d..bd2b76fb9c7 100644
--- a/lib/galaxy/app_unittest_utils/galaxy_mock.py
+++ b/lib/galaxy/app_unittest_utils/galaxy_mock.py
@@ -441,7 +441,7 @@ class MockTemplateHelpers:
         pass
 
     def dumps(*kwargs):
-        return {}
+        return kwargs
 
     def js(*js_files):
         pass
diff --git a/test/unit/app/visualizations/plugins/test_VisualizationsRegistry.py b/test/unit/app/visualizations/plugins/test_VisualizationsRegistry.py
index 6f5ce4274e7..54b36a4f64f 100644
--- a/test/unit/app/visualizations/plugins/test_VisualizationsRegistry.py
+++ b/test/unit/app/visualizations/plugins/test_VisualizationsRegistry.py
@@ -3,6 +3,7 @@ Test lib/galaxy/visualization/plugins/registry.
 """
 
 import os
+import re
 
 from galaxy.app_unittest_utils import galaxy_mock
 from galaxy.util import (
@@ -171,7 +172,8 @@ class TestVisualizationsRegistry(VisualizationsBase_TestCase):
         response = script_entry.render(trans=trans, embedded=True)
         assert '<script type="module" src="mysrc">' in response
         assert '<link rel="stylesheet" href="mycss">' in response
-        assert "<div id=\"mycontainer\" data-incoming='{}'></div>" in response
+        assert re.search(r'<div id="mycontainer" data-incoming=\'.*?\'></div>', response)
+        assert "'root': 'request.host_url/'" in response
         mock_app_dir.remove()