public void AddChecklistShouldReturnListItem() { //Arrange var mockRepo = new Mock <INoteRepository>(); var newlstItem = new Checklist { Content = "ef core db first", NoteId = 1 }; var resultlstItem = new Checklist { Content = "ef core db first", ChecklistId = 3, NoteId = 1 }; mockRepo.Setup(repo => repo.AddChecklist(newlstItem)).Returns(resultlstItem); var service = new NoteService(mockRepo.Object); //Act var actual = service.AddChecklist(1, newlstItem); //Assert Assert.IsAssignableFrom <Checklist>(actual); Assert.NotNull(actual); Assert.Equal("ef core db first", actual.Content); Assert.Equal(3, actual.ChecklistId); Assert.Equal(1, actual.NoteId); }