HOW-TO: Test these Drupal scaffold files

In order to test these scaffold files, you'll need to get the entire Drupal repo and
run the tests there.

You'll find the tests in core/tests/Drupal/Tests/ComposerIntegrationTest.php.

You can get the full Drupal repo here:
https://www.drupal.org/project/drupal/git-instructions

You can find more information about running PHPUnit tests with Drupal here:
https://www.drupal.org/node/2116263

You can run a single phpunit test file like so:

$ ./vendor/bin/phpunit -c core core/tests/Drupal/Tests/ComposerIntegrationTest.php