public void TestAddFileToFolder() { Folder fold5 = _folder.GetFolderByID(5); var newFile = new File { ID = 2, Content = "var x = 0;", Name = "init.js", Extension = ".js", Type = "javascript", FolderID = 2 }; _folder.AddFileToFolder(5, newFile); //Act List <File> allFiles = _folder.GetAllFilesById(fold5.ID); //Assert Assert.AreEqual(allFiles.Count, 1); Assert.AreEqual(allFiles.ElementAt(0).ID, newFile.ID); }