Update Command.php

Author: vearutop

src/TextUI/Command.php

@@ -338,13 +338,15 @@ protected function handleArguments(array $argv)
                     break;
 
                 case '--test-suffix':
-                    $o1 = isset($option[1]) ? $option[1] : '';
-                    $this->arguments['testSuffixes'] = explode(
-                        ',',
-                        $o1
-                    );
+                    $this->arguments['testSuffixes'] = [];
+                    if (isset($option[1])) {
+                        $this->arguments['testSuffixes'] = explode(
+                            ',',
+                            $option[1]
+                        );
+                    }
                     break;
-
+                
                 case '--include-path':
                     $includePath = $option[1];
                     break;