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PHPUnit Kernel Tests

When to Use

Write Kernel tests when you need to test integration with Drupal services, database operations, entity CRUD, or service container interactions without needing a full Drupal installation.

Decision

If you need... Use Kernel Tests Why
Test service integration Yes Access to container and dependency injection
Entity CRUD operations Yes Database and entity storage available
Configuration system Yes Config system fully functional
HTTP requests/responses No, use Functional No web server in Kernel tests
Test admin forms No, use Functional No routing or form rendering
Test JavaScript No, use FunctionalJavascript No browser environment

Pattern

<?php
namespace Drupal\Tests\my_module\Kernel;

use Drupal\KernelTests\KernelTestBase;
use Drupal\node\Entity\Node;
use Drupal\node\Entity\NodeType;
use Drupal\user\Entity\User;

/**
 * Tests the my_module entity processor service.
 *
 * @group my_module
 */
class EntityProcessorTest extends KernelTestBase {

  protected static $modules = [
    'system', 'user', 'node', 'field', 'text', 'my_module',
  ];

  protected function setUp(): void {
    parent::setUp();

    // Install database schemas
    $this->installEntitySchema('user');
    $this->installEntitySchema('node');

    // Install configuration
    $this->installConfig(['system', 'node', 'my_module']);

    // Create content type
    NodeType::create([
      'type' => 'article',
      'name' => 'Article',
    ])->save();

    // Create required users (user 0 = anonymous, user 1 = admin)
    User::create(['uid' => 0, 'name' => 'guest'])->save();
    User::create(['uid' => 1, 'name' => 'admin'])->save();
  }

  public function testEntityProcessing(): void {
    $node = Node::create([
      'type' => 'article',
      'title' => 'Test Article',
      'uid' => 1,
    ]);
    $node->save();

    // Test service from container
    $processor = $this->container->get('my_module.entity_processor');
    $result = $processor->process($node);

    $this->assertTrue($result['success']);
    $this->assertEquals('Test Article', $result['title']);
    $this->assertInstanceOf(Node::class, $result['entity']);
  }

  public function testConfigurationIntegration(): void {
    // Test configuration system
    $config = $this->config('my_module.settings');
    $config->set('api_enabled', TRUE)->save();

    $service = $this->container->get('my_module.api_client');
    $this->assertTrue($service->isEnabled());
  }
}

File Location: modules/my_module/tests/src/Kernel/EntityProcessorTest.php

Common Mistakes

  • Wrong: Not installing entity schemas → Right: Call installEntitySchema() for all entities used
  • Wrong: Not installing configuration → Right: Call installConfig() for modules with config
  • Wrong: Not creating required users (uid 0, 1) → Right: Create anonymous and admin users in setUp
  • Wrong: Forgetting to list all required modules in $modules → Right: Include all dependencies
  • Wrong: Using drupalGet() in Kernel tests → Right: Use Functional tests for HTTP layer

See Also