title: Running tests of a composer package in vendor directory
body: <p>I have a project I created with composer <code>create-project</code> command, but before running <code>composer install</code>, I added one more package to project <code>composer.json</code> file.
  After installing the packages, I correctly have all the dependencies including the one newly added in the vendor directory. What I want now is to run the tests of the package that I manually added to composer.json. I tried the below, but doesn't seem to run the tests of the said package</p>
  
  <pre><code>./vendor/bin/phpunit 
  </code></pre>