如何使用MOQ和存储库模式对MVP中的事件进行单元测试？

Question

I've had a look around and can't find anywhere to help me.

So the event on my view which I would like to unit test is my OnFormLoadEvent. It looks like this:

public partial class SystemVariablesForm : Form, ISystemVariablesView {

        private SystemVariablesPresenter presenter;
        private readonly ISystemVariablesManager manager;

        public SystemVariablesForm(ISystemVariablesManager _manager) {
            manager = _manager;
            InitializeComponent();
        }

        public float BindingLip {
            get {
                return (float)nudBindingLip.Value;
            }
            set => nudBindingLip.Value = (decimal)value;
        }
        public float HeadTrim {
            get {
                return (float)nudHeadTrim.Value;
            }
            set => nudHeadTrim.Value = (decimal)value;
        }
        public float FootTrim {
            get {
                return (float)nudFootTrim.Value;
            }
            set => nudFootTrim.Value = (decimal)value;
        }

        public string ErrorMessage {
            get {
                return lblErrors.Text;
            }
            set => lblErrors.Text = value;
        }
        public event EventHandler<EventArgs> SetSystemVariables;

        public event EventHandler<EventArgs> OnFormLoad;
        public event EventHandler<ErrorEventArgs> LogErrorToView;
        public event EventHandler<EventArgs> SetImpositionFormAsActive;

        private void SetSystemVariables_Load(object sender, EventArgs e) {
            //Have to do this to avoid a dependency injection loop as the view relies on the presenter and the presenter relies on the view
            presenter = new SystemVariablesPresenter(this, manager);
            try {
                OnFormLoad(this, e);
            }
            catch (Exception ex) {
                LogErrorToView(this, new ErrorEventArgs(ex.Message));
            }
        }
    }

This then gets picked up in my presenter in this method:

private void DisplaySystemVariables(object sender, EventArgs e) {
    try {
        SystemVariables variables = _systemVariablesManager.ReturnSystemVariables();
        _view.BindingLip = variables.BindingLip;
        _view.HeadTrim = variables.HeadTrim;
        _view.FootTrim = variables.FootTrim;
    }
    catch (Exception ex) {
        LogErrorToView(this, new ErrorEventArgs(ex.Message));
    }
}

This calls my manager:

  public class SystemVariablesManager : ISystemVariablesManager {
        private ISystemVariablesRepository _systemVariablesRepo;
        public SystemVariablesManager(ISystemVariablesRepository systemVariablesRepo) {
            _systemVariablesRepo = systemVariablesRepo;
        }    
        public Models.SystemVariables ReturnSystemVariables() {
            return _systemVariablesRepo.ReturnSystemVariables();
        }

        public void SetSystemVariables(Models.SystemVariables systemVariables) {
            _systemVariablesRepo.SetSystemVariables(systemVariables);
        }
    }

Which in turn calls my repository:

   public Models.SystemVariables ReturnSystemVariables() {
            if (File.Exists(expectedFilePath)) {
                var json = JObject.Parse(File.ReadAllText(expectedFilePath))["SystemVariables"];
                return JsonConvert.DeserializeObject<Models.SystemVariables>(json.ToString());
            }
            else {
                throw new Exception("Setup file not located. Please run the Inital Set up application. Please ask Andrew for more information.");
            }
        }

Now I need to test this event using unit tests, I have chosen MOQ but I'm unsure how I can use it to test this.

My unit test looks like this so far:

  [TestClass]
    public class SystemVariablesPresenterTests {

        [TestMethod]
        private void OnFomLoad() {
            var mockView = new Mock<ISystemVariablesView>();

            mockView.Raise(r => r.OnFormLoad += null, new EventArgs());

            Assert.IsNotNull(mockView.Object.HeadTrim);

        }
    }

How do I modify my unit test to call the repository/manager like the above steps?

Sorry, very new to this.

Answer 1

The mocked view is only your mock. You will also need to create the test target, which should be the presenter. I suppose there is a way to connect the mock view to the real presenter. You will also need to decide the boundary of your unit which is usually only the presenter. Then you will need to mock the external dependencies. Since the boundary is only the presenter, the manager is an external dependency which needs to be mocked. Basically you are only testing, when your mocked view fires an event, what your test target(the real presenter) is doing to the mocked manager. The repository is not involved in this process.

You can also take an pragmatic approach, and decide that the unit is the presenter and the manager combined together. Then the repository becomes an external dependency and needs to be mocked. Then you will be testing when the mocked view fires and event, what the test target(the real presenter + manager) is doing to the mocked repository.