Fix test command

Author: papac

.github/workflows/tests.yml

@@ -63,4 +63,4 @@ jobs:
         run: if [ ! -d /tmp/bowphp_testing ]; then mkdir -p /tmp/bowphp_testing; fi;
 
       - name: Run test suite
-        run: ./vendor/bin/phpunit tests 
+        run: ./vendor/bin/phpunit tests --configuration phpunit.dist.xml

src/Storage/Service/FTPService.php

@@ -251,7 +251,6 @@ public function disconnect(): void
     {
         if ($this->connection !== null) {
             @ftp_close($this->connection);
-            $this->connection = null;
             $this->is_connected = false;
         }
     }