diff --git a/src/Symfony/Component/Cache/Tests/Traits/RedisTraitTest.php b/src/Symfony/Component/Cache/Tests/Traits/RedisTraitTest.php
index e7e368b3e829d..e07ec82d7cec2 100644
--- a/src/Symfony/Component/Cache/Tests/Traits/RedisTraitTest.php
+++ b/src/Symfony/Component/Cache/Tests/Traits/RedisTraitTest.php
@@ -17,13 +17,6 @@
 
 class RedisTraitTest extends TestCase
 {
-    public static function setUpBeforeClass(): void
-    {
-        if (!getenv('REDIS_CLUSTER_HOSTS')) {
-            throw new SkippedTestSuiteError('REDIS_CLUSTER_HOSTS env var is not defined.');
-        }
-    }
-
     /**
      * @dataProvider provideCreateConnection
      */
@@ -65,4 +58,31 @@ public static function provideCreateConnection(): array
             ],
         ];
     }
+
+    public function testClearUsesValidType()
+    {
+        if (!class_exists(\Redis::class)) {
+            throw new SkippedTestSuiteError(sprintf('The "%s" class is required.', \Redis::class));
+        }
+        $redisMock = $this->getMockBuilder(\Redis::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+        $redisMock->method('info')->willReturn(['redis_version' => '3.0.0']);
+        $redisMock->expects(self::once())
+            ->method('scan')
+            ->with(null, 'some-namespace*', 1000, 'string')
+            ->willReturn([0, []]);
+        $mock = new class($redisMock) {
+            use RedisTrait {
+                doClear as public;
+            }
+
+            public function __construct($redis)
+            {
+                $this->redis = $redis;
+            }
+        };
+
+        $mock->doClear('some-namespace');
+    }
 }
diff --git a/src/Symfony/Component/Cache/Traits/RedisTrait.php b/src/Symfony/Component/Cache/Traits/RedisTrait.php
index 287c0ea962121..21460828fd030 100644
--- a/src/Symfony/Component/Cache/Traits/RedisTrait.php
+++ b/src/Symfony/Component/Cache/Traits/RedisTrait.php
@@ -476,7 +476,7 @@ protected function doClear(string $namespace)
 
             $cursor = null;
             do {
-                $keys = $host instanceof \Predis\ClientInterface ? $host->scan($cursor, 'MATCH', $pattern, 'COUNT', 1000) : $host->scan($cursor, $pattern, 1000);
+                $keys = $host instanceof \Predis\ClientInterface ? $host->scan($cursor, 'MATCH', $pattern, 'COUNT', 1000) : $host->scan($cursor, $pattern, 1000, 'string');
                 if (isset($keys[1]) && \is_array($keys[1])) {
                     $cursor = $keys[0];
                     $keys = $keys[1];