[tests] Update tests for Predis\Command\Command.

tests/Predis/Command/CommandTest.php

@@ -108,6 +108,13 @@ class CommandTest extends StandardTestCase
 
         $command->setHash($hash);
         $this->assertSame($hash, $command->getHash());
+
+        $command->setArguments(array('key'));
+        $this->assertNull($command->getHash());
+
+        $command->setHash($hash);
+        $command->setRawArguments(array('key'));
+        $this->assertNull($command->getHash());
     }
 
     /**