public function testAddFieldDefinitionThrowsInvalidArgumentExceptionDuplicateFieldIdentifier()
{
$contentTypeDraft = $this->createDraftContentType();
/* BEGIN: Use Case */
// $contentTypeDraft contains a ContentTypeDraft
// $contentTypeDraft has a field "title"
$contentTypeService = $this->repository->getContentTypeService();
$fieldDefCreate = $contentTypeService->newFieldDefinitionCreateStruct('title', 'string');
// Throws an exception
$contentTypeService->addFieldDefinition($contentTypeDraft, $fieldDefCreate);
/* END: Use Case */
}