Composer Include one folder

I wanted to include one directory form an svn repo.
With help of stackoverflow I found the solution.

"require-dev": {
    "wordpress/phpunit": "*"
},
"repositories": [
    {
        "type": "package",
        "package": {
            "name": "wordpress/phpunit",
            "version": "1.0.0",
            "source": {
                "url": "https://develop.svn.wordpress.org",
                "type": "svn",
                "reference": "trunk/tests/phpunit/includes/@43534"
            }
        }
    }
]

There is a downside, it won’t update. Unless you up the version inside the repositories block.
The upside is that this is lightweight, especially if the rest of the repo is big.
This is rarely the right solution.