Setting up PSR-4 module

autoload_psr4.php

<?php

// autoload_psr4.php @generated by Composer

$vendorDir = dirname(dirname(__FILE__));
$baseDir = dirname($vendorDir);

return array(
/*...*/
    'Behat\\Mink\\Driver\\' => array($vendorDir . '/behat/mink-browserkit-driver/src', $vendorDir . '/behat/mink-goutte-driver/src', $vendorDir . '/behat/mink-selenium2-driver/src'),
    'Behat\\Mink\\' => array($vendorDir . '/behat/mink/src'),
    'MyNamespace\\Traits\\' => array($vendorDir . '/my-namespace/amazon-traits/src'),
);

included_package_composer.json

{
    "name": "my-namespace/amazon-traits",
    "description": "Traits for s3 etc.",
    "require": {
        "php": ">=5.4.0",
        "aws/aws-sdk-php": "2.*"
    },
    "autoload": {
        "psr-4": {
            "MyNamespace\\Traits\\": "src/"
        }
    },
    "minimum-stability": "stable"
}

package_tree

➜  pwd
/path/to/parent-project/vendor/my-namespace/amazon-traits
➜  tree
.
├── composer.json
├── README.md
└── src
    └── AmazonTraits.php

1 directory, 3 files

parent_composer.json

{
  "name": "my-namespace/isicheckerservice",
  "require": {
    "behat/mink-goutte-driver": "*",
    "behat/mink-selenium2-driver": "*",
    "my-namespace/amazon-traits": "dev-master",
	},
    "repositories": [
      {
        "type": "vcs",
        "url": "[email protected]:my-namespace/amazon-traits.git"
      }
    ],
	"minimum-stability": "dev"
}