class FieldKernelTestBase

abstract class FieldKernelTestBase extends KernelTestBase {
    
    /**
     * Modules to enable.
     *
     * @var array
     */
    protected static $modules = [
        'user',
        'system',
        'field',
        'text',
        'entity_test',
        'field_test',
    ];
    
    /**
     * Bag of created field storages and fields.
     *
     * Allows easy access to test field storage/field names/IDs/objects via:
     * - $this->fieldTestData->field_name[suffix]
     * - $this->fieldTestData->field_storage[suffix]
     * - $this->fieldTestData->field_storage_uuid[suffix]
     * - $this->fieldTestData->field[suffix]
     * - $this->fieldTestData->field_definition[suffix]
     *
     * @see \Drupal\field\Tests\FieldUnitTestBase::createFieldWithStorage()
     *
     * @var \ArrayObject
     */
    protected $fieldTestData;
    
    /**
     * @var string
     */
    protected $entityId;
    
    /**
     * Set the default field storage backend for fields created during tests.
     */
    protected function setUp() {
        parent::setUp();
        $this->fieldTestData = new \ArrayObject([], \ArrayObject::ARRAY_AS_PROPS);
        $this->installEntitySchema('entity_test');
        $this->installEntitySchema('user');
        $this->installSchema('system', [
            'sequences',
        ]);
        // Set default storage backend and configure the theme system.
        $this->installConfig([
            'field',
            'system',
        ]);
        // Create user 1.
        $storage = \Drupal::entityTypeManager()->getStorage('user');
        $storage->create([
            'uid' => 1,
            'name' => 'entity-test',
            'mail' => 'entity@localhost',
            'status' => TRUE,
        ])
            ->save();
    }
    
    /**
     * Create a field and an associated field storage.
     *
     * @param string $suffix
     *   (optional) A string that should only contain characters that are valid in
     *   PHP variable names as well.
     * @param string $entity_type
     *   (optional) The entity type on which the field should be created.
     *   Defaults to "entity_test".
     * @param string $bundle
     *   (optional) The entity type on which the field should be created.
     *   Defaults to the default bundle of the entity type.
     */
    protected function createFieldWithStorage($suffix = '', $entity_type = 'entity_test', $bundle = NULL) {
        if (empty($bundle)) {
            $bundle = $entity_type;
        }
        $field_name = 'field_name' . $suffix;
        $field_storage = 'field_storage' . $suffix;
        $field_storage_uuid = 'field_storage_uuid' . $suffix;
        $field = 'field' . $suffix;
        $field_definition = 'field_definition' . $suffix;
        $this->fieldTestData->{$field_name} = mb_strtolower($this->randomMachineName() . '_field_name' . $suffix);
        $this->fieldTestData->{$field_storage} = FieldStorageConfig::create([
            'field_name' => $this->fieldTestData->{$field_name},
            'entity_type' => $entity_type,
            'type' => 'test_field',
            'cardinality' => 4,
        ]);
        $this->fieldTestData->{$field_storage}
            ->save();
        $this->fieldTestData->{$field_storage_uuid} = $this->fieldTestData->{$field_storage}
            ->uuid();
        $this->fieldTestData->{$field_definition} = [
            'field_storage' => $this->fieldTestData->{$field_storage},
            'bundle' => $bundle,
            'label' => $this->randomMachineName() . '_label',
            'description' => $this->randomMachineName() . '_description',
            'settings' => [
                'test_field_setting' => $this->randomMachineName(),
            ],
        ];
        $this->fieldTestData->{$field} = FieldConfig::create($this->fieldTestData->{$field_definition});
        $this->fieldTestData->{$field}
            ->save();
        \Drupal::service('entity_display.repository')->getFormDisplay($entity_type, $bundle)
            ->setComponent($this->fieldTestData->{$field_name}, [
            'type' => 'test_field_widget',
            'settings' => [
                'test_widget_setting' => $this->randomMachineName(),
            ],
        ])
            ->save();
    }
    
    /**
     * Saves and reloads an entity.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity to save.
     *
     * @return \Drupal\Core\Entity\EntityInterface
     *   The entity, freshly reloaded from storage.
     */
    protected function entitySaveReload(EntityInterface $entity) {
        $entity->save();
        $controller = $this->container
            ->get('entity_type.manager')
            ->getStorage($entity->getEntityTypeId());
        $controller->resetCache();
        return $controller->load($entity->id());
    }
    
    /**
     * Validate and save entity. Fail if violations are found.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity to save.
     */
    protected function entityValidateAndSave(EntityInterface $entity) {
        $violations = $entity->validate();
        if ($violations->count()) {
            $this->fail($violations);
        }
        else {
            $entity->save();
        }
    }
    
    /**
     * Generate random values for a field_test field.
     *
     * @param $cardinality
     *   Number of values to generate.
     *
     * @return array
     *   An array of random values, in the format expected for field values.
     */
    protected function _generateTestFieldValues($cardinality) {
        $values = [];
        for ($i = 0; $i < $cardinality; $i++) {
            // field_test fields treat 0 as 'empty value'.
            $values[$i]['value'] = mt_rand(1, 127);
        }
        return $values;
    }
    
    /**
     * Assert that a field has the expected values in an entity.
     *
     * This function only checks a single column in the field values.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity to test.
     * @param $field_name
     *   The name of the field to test
     * @param $expected_values
     *   The array of expected values.
     * @param $langcode
     *   (Optional) The language code for the values. Defaults to
     *   \Drupal\Core\Language\LanguageInterface::LANGCODE_NOT_SPECIFIED.
     * @param $column
     *   (Optional) The name of the column to check. Defaults to 'value'.
     */
    protected function assertFieldValues(EntityInterface $entity, $field_name, $expected_values, $langcode = LanguageInterface::LANGCODE_NOT_SPECIFIED, $column = 'value') {
        $expected_values_count = count($expected_values);
        // Re-load the entity to make sure we have the latest changes.
        $storage = $this->container
            ->get('entity_type.manager')
            ->getStorage($entity->getEntityTypeId());
        $storage->resetCache([
            $entity->id(),
        ]);
        $e = $storage->load($this->entityId);
        $field = $values = $e->getTranslation($langcode)->{$field_name};
        // Filter out empty values so that they don't mess with the assertions.
        $field->filterEmptyItems();
        $values = $field->getValue();
        $this->assertCount($expected_values_count, $values, 'Expected number of values were saved.');
        foreach ($expected_values as $key => $value) {
            $this->assertEquals($value, $values[$key][$column], new FormattableMarkup('Value @value was saved correctly.', [
                '@value' => $value,
            ]));
        }
    }

}