Gets list of changed files test fixed

Author: igorsgm

tests/Unit/Traits/GitHelperTest.php

@@ -12,7 +12,7 @@
     chdir(__DIR__);
 
     expect($this->getListOfChangedFiles())->toBe(
-        shell_exec('git status --short')
+        shell_exec('git status --short') ?? ''
     );
 });