public async Task GetPartContent() { DbModel.Message testMessage1 = await GetTestMessage1(); TestMessagesRepository messagesRepository = new TestMessagesRepository(testMessage1); MessagesController messagesController = new MessagesController(messagesRepository); var parts = messagesController.GetMessage(testMessage1.Id).Parts.Flatten(p => p.ChildParts).SelectMany(p => p.Attachments); var part = parts.First(p => p.FileName == "file2"); var result = messagesController.GetPartContent(testMessage1.Id, part.Id); var stringResult = await new StreamReader(result.FileStream, Encoding.UTF8).ReadToEndAsync(); Assert.Equal(testMessage1File2Content, stringResult); }