install after download

[pishguy]

how to install after download this source, i'm using composer install and i get this error:

Generating autoload files



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

[connor11528]

I am getting a different error:

$ composer install
Loading composer repositories with package information
Installing dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - laravel/framework v5.0.9 requires ext-mcrypt * -> the requested PHP extension mcrypt is missing from your system.
    - laravel/framework v5.0.8 requires ext-mcrypt * -> the requested PHP extension mcrypt is missing from your system.
    - laravel/framework v5.0.7 requires ext-mcrypt * -> the requested PHP extension mcrypt is missing from your system.
    - laravel/framework v5.0.6 requires ext-mcrypt * -> the requested PHP extension mcrypt is missing from your system.
    - laravel/framework v5.0.5 requires ext-mcrypt * -> the requested PHP extension mcrypt is missing from your system.
    - laravel/framework v5.0.4 requires ext-mcrypt * -> the requested PHP extension mcrypt is missing from your system.
    - laravel/framework v5.0.34 requires ext-mcrypt * -> the requested PHP extension mcrypt is missing from your system.