diff --git a/tests/actual_test_cases.php b/tests/actual_test_cases.php
index 318e678..0b80e2f 100644
--- a/tests/actual_test_cases.php
+++ b/tests/actual_test_cases.php
@@ -162,10 +162,11 @@ function multilang2_actual_test_cases(): array {
             '¡Hola!
              This text is common for all languages because it is outside of all lang blocks.
              ',
-            '{mlang other}Hello!{mlang}{mlang es,es_mx}¡Hola!{mlang}
+            '{mlang other}Hello!{mlang}{mlang es}¡Hola!{mlang}
              This text is common for all languages because it is outside of all lang blocks.
              {mlang other}Bye!{mlang}{mlang it}Ciao!{mlang}',
-            'es_mx', ['es_mx' => 'es'],
+            'es_mx',
+            ['es_mx' => 'es'],
         ],
         [
             '
diff --git a/tests/filter_test.php b/tests/filter_test.php
index a5aa772..525f1c2 100644
--- a/tests/filter_test.php
+++ b/tests/filter_test.php
@@ -70,6 +70,11 @@ protected function setup_parent_language(string $child, string $parent): void {
         check_dir_exists($langfolder);
         $langconfig = "<?php\n\$string['parentlanguage'] = '$parent';";
         file_put_contents($langfolder . '/langconfig.php', $langconfig);
+
+        $langfolder = $CFG->dataroot . '/lang/' . $parent;
+        check_dir_exists($langfolder);
+        $langconfig = "<?php\n\$string['parentlanguage'] = '';";
+        file_put_contents($langfolder . '/langconfig.php', $langconfig);
     }
 
     /**