dependency-injection-as-a-tool-for-testing-inject-bar.php

<?php

class Foo
{
    protected $bar;

    public function doSomething($bar, $id, $name, $email)
    {
        $this->bar = $bar;
        // .. possibly manipulate $id, $name and $email

        // assume we want to edit a row in a database and
        // then return an array of data containing that row
        return $this->bar->editAndReturnUser($id, $name, $email);
    }
}