ComputedFieldTest.php

<?php

namespace Drupal\Tests\views\Kernel\Handler;

use Drupal\entity_test\Entity\EntityTestComputedField;
use Drupal\Tests\views\Kernel\ViewsKernelTestBase;
use Drupal\views\Views;

/**
 * Provides some integration tests for the Field handler.
 *
 * @see \Drupal\views\Plugin\views\field\EntityField
 * @group views
 */
class ComputedFieldTest extends ViewsKernelTestBase {
    
    /**
     * Views to be enabled.
     *
     * @var array
     */
    public static $testViews = [
        'computed_field_view',
    ];
    
    /**
     * Modules to enable.
     *
     * @var array
     */
    public static $modules = [
        'entity_test',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected function setUp($import_test_views = TRUE) {
        parent::setUp($import_test_views);
        $this->installEntitySchema('entity_test_computed_field');
    }
    
    /**
     * Test the computed field handler.
     */
    public function testComputedFieldHandler() {
        \Drupal::state()->set('entity_test_computed_field_item_list_value', [
            'computed string',
        ]);
        $entity = EntityTestComputedField::create([]);
        $entity->save();
        $view = Views::getView('computed_field_view');
        $rendered_view = $view->preview();
        $output = $this->container
            ->get('renderer')
            ->renderRoot($rendered_view);
        $this->assertStringContainsString('computed string', (string) $output);
    }

}