testing.md

Testing

This application relies on PHPUnit along with Panther for application tests.

Panther

Panther is a library to scrape websites and to run end-to-end tests using real browsers (and so executes Javascript and CSS). It is based on the same API as Symfony's WebTestCase and as such is fully compatible with it, with some additional functions described in its documentation.

Using it requires installing either chromedriver or geckodriver on the testing platform. For this we don't use the Composer alternative as it tends to have issues with the versions it installs and recommend using the OS' package manager.

Basic usage requires for the test class to extend PantherTestCase and create a Panther client.

For more flexibility we can use the PANTHER_BROWSER environment variable to choose which driver to use (chrome or firefox). This variable is not a part of Panther itself but allows testing the application against different browsers on-the-fly.

Setting the PANTHER_ERROR_SCREENSHOT_DIR environment variable allows Panther to take screenshots when a test fails.

Setting the PANTHER_NO_HEADLESS environment variable will display the browser window, which can be useful to debug.

Here is some sample code of a test class using Panther:

use Symfony\Component\Panther\PantherTestCase;

class DefaultControllerTest extends PantherTestCase
{
    protected $client;

    public function setUp(): void
    {
        $browser = array_key_exists('PANTHER_BROWSER', $_SERVER) ? $_SERVER['PANTHER_BROWSER'] : self::CHROME;
        $this->client  = static::createPantherClient(['browser' => $browser]);
    }

    public function testIndex(): void
    {
        $crawler = $this->client->request('GET', '/');
        $this->assertSelectorExists('body');
    }
}