diff --git a/tests/mutex/MutexConcurrencyTest.php b/tests/mutex/MutexConcurrencyTest.php
index 74608a3c..cafca6d7 100644
--- a/tests/mutex/MutexConcurrencyTest.php
+++ b/tests/mutex/MutexConcurrencyTest.php
@@ -108,7 +108,7 @@ public function testHighContention(callable $code, callable $mutexFactory)
     /**
      * Returns test cases for testHighContention().
      */
-    public static function provideHighContentionCases(): iterable
+    public function provideHighContentionCases(): iterable
     {
         $cases = array_map(function (array $mutexFactory): array {
             $filename = tempnam(sys_get_temp_dir(), 'php-lock-high-contention');