public async void GetDocumentAsync()
        {
            _logger.LogInformation("GetDocumentAsync...");
            var pageRequest = new PageRequest()
            {
                SortBy    = "LastWrite",
                SortOrder = SortOrders.DESC,
                PageIndex = 0,
                PageSize  = 50
            };

            using (var dbConnection = await _dbConnectionFactory.OpenUserConnectionAsync(_userId))
            {
                var result = await _repository.GetDocumentsAsync(dbConnection, pageRequest);

                Assert.NotNull(result);

                var firstDocument = result.Items.First();
                Assert.Empty(firstDocument.Data);

                var document = await _repository.GetDocumentAsync(dbConnection, firstDocument.DocumentId);

                Assert.NotEmpty(document.Data);
            }
        }
        private async Task <Document> GetDocument(int documentId)
        {
            var document = await _documentsRepository.GetDocumentAsync(documentId).ConfigureAwait(false);

            if (document == null)
            {
                throw new ServiceException(ErrorCodes.FileNotExist, "this document is not exist anymore");
            }

            return(document);
        }