Laravel 5.2 composer update

When I try to run a composer command like composer update it will throw an error.

Loading composer repositories with package information
Updating dependencies (including require-dev)
Nothing to install or update
Generating autoload files


  [RuntimeException]                                                           
  Could not scan for classes inside "tests/TestCase.php" which does not appear to be a file nor a folder                                                  


update [--prefer-source] [--prefer-dist] [--dry-run] [--dev] [--no-dev] [--lock] [--no-custom-installers] [--no-autoloader] [--no-scripts] [--no-progress] [--with-dependencies] [-v|vv|vvv|--verbose] [-o|--optimize-autoloader] [-a|--classmap-authoritative] [--ignore-platform-reqs] [--prefer-stable] [--prefer-lowest] [-i|--interactive] [--root-reqs] [--] [<packages>]...

I try to require a package Image

http://ift.tt/1qIKPb0

I'm using Laravel 5.2 on OSX 10.11.5 with PHP 5.6

via Chebli Mohamed