diff --git a/classes/helper.php b/classes/helper.php
index aa831134..6bffc96b 100644
--- a/classes/helper.php
+++ b/classes/helper.php
@@ -444,7 +444,9 @@ public static function sanitize_json_string(string $jsonstring): string {
         foreach ($json as $key => $value) {
             unset($json[$key]);
             $key = clean_param(clean_param($key, PARAM_CLEANHTML), PARAM_NOTAGS);
-            $json[$key] = is_array($value) ? clean_param_array($value, PARAM_CLEANHTML, true) : clean_param($value, PARAM_CLEANHTML);
+            $json[$key] = is_array($value)
+                ? clean_param_array($value, PARAM_CLEANHTML, true)
+                : clean_param($value, PARAM_CLEANHTML);
         }
         return json_encode($json);
     }
diff --git a/tests/boardmanager_test.php b/tests/boardmanager_test.php
index 5e607408..09f23e7a 100644
--- a/tests/boardmanager_test.php
+++ b/tests/boardmanager_test.php
@@ -321,9 +321,9 @@ public function test_can_user_manage_specific_card() {
     /**
      * Tests the json sanitization function.
      *
-     * @dataProvider test_sanitize_json_string_provider
-     * @param $jsonstring string the json string to sanitize
-     * @param $sanitized string the expected sanitized json string
+     * @dataProvider sanitize_json_string_provider
+     * @param string $jsonstring the json string to sanitize
+     * @param string $sanitized the expected sanitized json string
      * @return void
      */
     public function test_sanitize_json_string(string $jsonstring, string $sanitized): void {
@@ -336,24 +336,24 @@ public function test_sanitize_json_string(string $jsonstring, string $sanitized)
      *
      * @return array[] containing the keys 'json' and 'expected'
      */
-    public function test_sanitize_json_string_provider(): array {
+    public static function sanitize_json_string_provider(): array {
         return [
             [
                 'json' => '{"test": "<b>bad html</b><script>console.log(\"bla\")</script>"}',
-                'expected' => '{"test":"<b>bad html<\/b>"}'
+                'expected' => '{"test":"<b>bad html<\/b>"}',
             ],
             [
                 'json' => '{"test": "<b>good html</b>"}',
-                'expected' => '{"test":"<b>good html<\/b>"}'
+                'expected' => '{"test":"<b>good html<\/b>"}',
             ],
             [
                 'json' => '{"test": "<b>good html</b>","anotherkey": [{"nestedkey":"<script>console.log(\"bla\");</script>"}]}',
-                'expected' => '{"test":"<b>good html<\/b>","anotherkey":[{"nestedkey":""}]}'
+                'expected' => '{"test":"<b>good html<\/b>","anotherkey":[{"nestedkey":""}]}',
             ],
             [
                 'json' => '{"te<script>console.log(\"bla\");</script>st": "<b>good html</b>"}',
-                'expected' => '{"test":"<b>good html<\/b>"}'
-            ]
+                'expected' => '{"test":"<b>good html<\/b>"}',
+            ],
         ];
     }
 }