diff --git a/admin/tool/templatelibrary/tests/externallib_test.php b/admin/tool/templatelibrary/tests/externallib_test.php
index ac31ab64176..5dc0ff00b36 100644
--- a/admin/tool/templatelibrary/tests/externallib_test.php
+++ b/admin/tool/templatelibrary/tests/externallib_test.php
@@ -70,7 +70,7 @@ class tool_templatelibrary_external_testcase extends externallib_advanced_testca
 
         $originaltheme = $CFG->theme;
         // Change the theme to 'base' because it overrides these templates.
-        $CFG->theme = 'base';
+        $CFG->theme = 'boost';
 
         $template = external::load_canonical_template('core', 'notification_error');