class TimestampItemTest

class TimestampItemTest extends FieldKernelTestBase {
  
  /**
   * A field storage to use in this test class.
   *
   * @var \Drupal\field\Entity\FieldStorageConfig
   */
  protected $fieldStorage;
  
  /**
   * The field used in this test class.
   *
   * @var \Drupal\field\Entity\FieldConfig
   */
  protected $field;
  
  /**
   * {@inheritdoc}
   */
  protected function setUp() {
    parent::setUp();
    // Create a field with settings to validate.
    $this->fieldStorage = FieldStorageConfig::create([
      'field_name' => 'field_timestamp',
      'type' => 'timestamp',
      'entity_type' => 'entity_test',
    ]);
    $this->fieldStorage
      ->save();
    $this->field = FieldConfig::create([
      'field_storage' => $this->fieldStorage,
      'bundle' => 'entity_test',
    ]);
    $this->field
      ->save();
  }
  
  /**
   * Tests using entity fields of the datetime field type.
   */
  public function testDateTime() {
    // Verify entity creation.
    $entity = EntityTest::create();
    $value = 1488914208;
    $entity->field_timestamp = $value;
    $entity->name->value = $this->randomMachineName();
    $this->entityValidateAndSave($entity);
    // Verify entity has been created properly.
    $id = $entity->id();
    $entity = EntityTest::load($id);
    $this->assertInstanceOf(FieldItemListInterface::class, $entity->field_timestamp);
    $this->assertInstanceOf(FieldItemInterface::class, $entity->field_timestamp[0]);
    $this->assertEquals($entity->field_timestamp->value, $value);
    $this->assertEquals($entity->field_timestamp[0]->value, $value);
    // Verify changing the date value.
    $new_value = 1488914000;
    $entity->field_timestamp->value = $new_value;
    $this->assertEquals($entity->field_timestamp->value, $new_value);
    // Read changed entity and assert changed values.
    $this->entityValidateAndSave($entity);
    $entity = EntityTest::load($id);
    $this->assertEquals($entity->field_timestamp->value, $new_value);
    // Test sample item generation.
    $entity = EntityTest::create();
    $entity->field_timestamp
      ->generateSampleItems();
    $this->entityValidateAndSave($entity);
    // Ensure there is sample value a generated for the field.
    $this->assertNotNull($entity->field_timestamp->value);
  }

}