Why, Fatal error: Class 'PHPUnit_Framework_TestCase' not found in ...?

For those arriving here after updating phpunit to version 6 or greater released on 2017-02-03 (e.g. with composer), you may be getting this error because phpunit code is now namespaced (check changelog).

You will need to refactor things like \PHPUnit_Framework_TestCase to \PHPUnit\Framework\TestCase

The PHPUnit documentation says used to say to include/require PHPUnit/Framework.php, as follows:

require_once ('PHPUnit/Framework/TestCase.php');


As of PHPUnit 3.5, there is a built-in autoloader class that will handle this for you:

require_once 'PHPUnit/Autoload.php';

Thanks to Phoenix for pointing this out!

For higher version of phpunit such as 6.4 You must use the namespace PHPUnit\Framework\TestCase

use TestCase instead PHPUnit_Framework_TestCase

// use the following namespace
use PHPUnit\Framework\TestCase;

// extend using TestCase instead PHPUnit_Framework_TestCase
class SampleTest extends TestCase {