diff --git a/tests/mutex/MutexConcurrencyTest.php b/tests/mutex/MutexConcurrencyTest.php
index ad5c6f05..381e2d86 100644
--- a/tests/mutex/MutexConcurrencyTest.php
+++ b/tests/mutex/MutexConcurrencyTest.php
@@ -89,7 +89,7 @@ private function fork(int $concurrency, \Closure $code): void
     public function testHighContention(\Closure $code, \Closure $mutexFactory): void
     {
         $concurrency = 10;
-        $iterations = 1000 / $concurrency;
+        $iterations = 30 / $concurrency;
         $timeout = $concurrency * 20;
 
         $this->fork($concurrency, static function () use ($mutexFactory, $timeout, $iterations, $code): void {
@@ -110,6 +110,8 @@ public function testHighContention(\Closure $code, \Closure $mutexFactory): void
      */
     public static function provideHighContentionCases(): iterable
     {
+        $uris = explode(',', getenv('REDIS_URIS'));
+
         $cases = array_map(static function (array $mutexFactory): array {
             $filename = tempnam(sys_get_temp_dir(), 'php-lock-high-contention');
 
@@ -128,9 +130,18 @@ static function (int $increment) use ($filename): int {
                 },
                 $mutexFactory[0],
             ];
-        }, static::provideExecutionIsSerializedWhenLockedCases());
+        }, [
+            'PredisMutex' => [static function ($timeout) use ($uris): Mutex {
+                $clients = array_map(
+                    static fn ($uri) => new Client($uri),
+                    $uris
+                );
 
-        $addPDO = static function (string $dsn, string $user, string $password, string $vendor) use (&$cases) {
+                return new PredisMutex($clients, 'test', $timeout);
+            }],
+        ]);
+
+        /* $addPDO = static function (string $dsn, string $user, string $password, string $vendor) use (&$cases) {
             $pdo = self::getPDO($dsn, $user, $password);
 
             $options = ['mysql' => 'engine=InnoDB'];
@@ -184,7 +195,7 @@ static function ($timeout) use ($dsn, $user, $password) {
             $user = getenv('PGSQL_USER');
             $password = getenv('PGSQL_PASSWORD');
             $addPDO($dsn, $user, $password, 'postgres');
-        }
+        } */
 
         return $cases;
     }