isStorageRequired example

switch ($field_name) {
        case 'thread':
          // Improves the performance of the comment__num_new index defined           // in getEntitySchema().           $schema['fields'][$field_name]['not null'] = TRUE;
          break;

        case 'entity_type':
        case 'field_name':
          assert($storage_definition instanceof RequiredFieldStorageDefinitionInterface);
          if ($storage_definition->isStorageRequired()) {
            // The 'entity_type' and 'field_name' are required so they also need             // to be marked as NOT NULL.             $schema['fields'][$field_name]['not null'] = TRUE;
          }
          break;

        case 'created':
          $this->addSharedTableFieldIndex($storage_definition, $schema, TRUE);
          break;

        case 'uid':
          

$this->assertFalse($definition->isRequired());
  }

  /** * Tests storage required. * * @covers ::isStorageRequired * @covers ::setStorageRequired */
  public function testFieldStorageRequired() {
    $definition = BaseFieldDefinition::create($this->fieldType);
    $this->assertFalse($definition->isStorageRequired());
    $definition->setStorageRequired(TRUE);
    $this->assertTrue($definition->isStorageRequired());
    $definition->setStorageRequired(FALSE);
    $this->assertFalse($definition->isStorageRequired());
  }

  /** * Tests provider. * * @covers ::getProvider * @covers ::setProvider */