BookInstallTest.php

<?php

namespace Drupal\Tests\book\Kernel;

use Drupal\KernelTests\KernelTestBase;
use Drupal\node\Entity\NodeType;

/**
 * Test installation of Book module.
 *
 * @group book
 */
class BookInstallTest extends KernelTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected static $modules = [
        'node',
        'system',
    ];
    
    /**
     * Test Book install with pre-existing content type.
     *
     * Tests that Book module can be installed if content type with machine name
     * 'book' already exists.
     */
    public function testBookInstallWithPreexistingContentType() {
        // Create a 'book' content type.
        NodeType::create([
            'type' => 'book',
        ])->save();
        // Install the Book module. Using the module installer service ensures that
        // all the install rituals, including default and optional configuration
        // import, are performed.
        $status = $this->container
            ->get('module_installer')
            ->install([
            'book',
        ]);
        $this->assertTrue($status, 'Book module installed successfully');
    }

}