public void ItShouldNotAddSameTaskToTaskList() { var testAddCommand = new AddCommand(); var arguments = new ArgumentList(new string[] { "add", "I added something" }, new string[] { "add" }); var taskList = new TaskList(); Task testTask1 = new Task(); testTask1.TaskDescription = "I added something"; taskList.AddTask(ref testTask1); testAddCommand.Execute(arguments, taskList, new TagList(), new TagFolder()); int actual = taskList.GetListSize(); int expected = 1; Assert.AreEqual(expected, actual); }