public async Task Update_File_Contents() { var rnd = new Random(); var data = new byte[100]; rnd.NextBytes(data); //Create a unique file name var fileName = Guid.NewGuid().ToString(); //Upload a file var upload = _filesApi.CreateFile(fileName, _testFolder, data.Length, data); //Create new file data var newData = new byte[200]; rnd.NextBytes(data); //Update file contents var updatedFile = _filesApi.UpdateFileContents(upload.Id, newData.Length, newData); Assert.AreEqual(200, updatedFile.Size); //Create buffer for download var downloadedFile = new byte[200]; //Download file var wait = new WaitForVirusScan(_filesApi); (await wait.DownloadFileWithRetry(upload.Id)).Read(downloadedFile); Assert.AreEqual(newData, downloadedFile); }