[tests] Missing @requiresRedisVersion for HSTRLEN.

tests/Predis/Command/HashStringLengthTest.php

@@ -61,6 +61,7 @@ class HashStringLengthTest extends PredisCommandTestCase
 
     /**
      * @group connected
+     * @requiresRedisVersion >= 3.2.0
      */
     public function testReturnsStringLengthOfSpecifiedField()
     {
@@ -81,6 +82,7 @@ class HashStringLengthTest extends PredisCommandTestCase
 
     /**
      * @group connected
+     * @requiresRedisVersion >= 3.2.0
      * @expectedException \Predis\Response\ServerException
      * @expectedExceptionMessage Operation against a key holding the wrong kind of value
      */