Need help testing Binding in Windows Phone 8 - unit-testing

Question

I hope someone has already faced and solved this issue, and can point me to the correct direction.
So I have rest of my unit tests working: Core.Tests has tests for ViewModels to see they are working properly. Now I would like to set up a test project for Phone.Tests that would only test out the binding. So suppose on the login page, something get's entered into the username text box, and that value should be updated in ViewModel and vice-versa.
As a testing framework, I am using WP Toolkit Test framework, and not MS one; WP Toolkit framework runs on the phone itself, meaning it has access to the UI thread.
In theory a test is supposed to look like following:
[TestMethod]
[Asynchronous]
public void Username_Update_View_Should_Update_Model()
{
const string testUsername = "Testing";
var usernameTextBox = GetUiElement<PhoneTextBox>("UsernamePhoneTextBox");
// initial value
Assert.AreEqual(null, _viewModel.Authorization.Username, "Default value should be blank");
//
usernameTextBox.Text = testUsername;
//
Assert.AreEqual(testUsername, _viewModel.Authorization.Username, "Binding not set for {0}", "Username");
}
private T GetUiElement<T>(string name) where T : UIElement
{
return (T)_view.FindName(name);
}
Now, I need to somehow create the view in [TestInitialize] method, and this is what I think I have setup wrong.
I have tried creating the ViewModel manually; then I created the View manually, and binded both DataContext and ViewModel (just to be on safe side) to created viewModel.
At this point, I am expecting changing one property on any one should update the other.
Of-course the error is my test fails. I can't figure out if I should be looking at a custom presenter (all the examples seem to be for ios, droid.) I also tried the following:
public class TestAppStart : MvxNavigatingObject, IMvxAppStart
{
public void Start(object hint = null)
{
ShowViewModel<UserLoginViewModel>();
}
}
and then on my testInitialize I thought I could start it, but I guess I need to find RegisterAppStart and once that's done, try to get the view back from RootFrame.
There must be an easier way... anyone??
Thanks in advance.
Edited: I have got this following as Base Test
public abstract class BaseTest
{
private IMvxIoCProvider _ioc;
protected IMvxIoCProvider Ioc
{
get
{
return _ioc;
}
}
public void Setup()
{
ClearAll();
}
protected virtual void ClearAll()
{
MvxSingleton.ClearAllSingletons();
_ioc = MvxSimpleIoCContainer.Initialize();
_ioc.RegisterSingleton(_ioc);
_ioc.RegisterSingleton((IMvxTrace)new DebugTrace());
InitialiseSingletonCache();
InitialiseMvxSettings();
MvxTrace.Initialize();
AdditionalSetup();
}
private static void InitialiseSingletonCache()
{
MvxSingletonCache.Initialize();
}
protected virtual void InitialiseMvxSettings()
{
_ioc.RegisterSingleton((IMvxSettings)new MvxSettings());
}
protected virtual void AdditionalSetup()
{
_ioc.RegisterSingleton(Mock.Of<ISettings>);
_ioc.RegisterSingleton<IApplicationData>(() => new ApplicationData());
_ioc.RegisterSingleton<IPlatformSpecific>(() => new PlatformSpecific());
_ioc.RegisterSingleton<IValidatorFactory>(() => new ValidatorFactory());
//
_ioc.RegisterType<IMvxMessenger, MvxMessengerHub>();
}
}
On my TestClass initialize, I call base.Setup(), which does setup except the ViewDispatcher. Unfortunately I can't figure out how to use that dispatcher:
I guess really the question I am asking is: how do I get a View through MvvmCross.
PS: I am actually surprised that most don't test the bindings; isn't it where the most amount of mistakes is likely to happen? I am pretty sure the project compiles even if I had bad binding :) scary kind of reminds me of early asp days.
PS: I have actually got another testProject that tests the ViewModels; on that testProject I have managed to hookup following the guidelines at
http://blog.fire-development.com/2013/06/29/mvvmcross-unit-testing-with-autofixture/
Which works beautifully; and also uses autoFixture, NSubstitute and xUnit: and I can't use any of them in Phone Test project.

Answer 1

From my experience, testing the bindings themselves is pretty unusual - most developers stop their testing at the ViewModel and ValueConverter level.
However, if you want to test the bindings, then this should be possible. I suspect the only problem in your current tests is that you haven't initialised any of the MvvmCross infrastructure and so MvxViewModel isn't able to propagate INotifyPropertyChanged events.
If you want to initialise this part of the MvvmCross infrastructure, then be sure to initialise at least:
the MvvmCross IoC container
the MvvmCross main thread dispatcher
This is similar to what is done in the unit tests in the N=29 video - see https://github.com/MvvmCross/NPlus1DaysOfMvvmCross/blob/master/N-29-TipCalcTest/TipCalcTest.Tests/FirstViewModelTests.cs#L57
For your app, you can do this using something like:
public static class MiniSetup
{
public static readonly MiniSetup Instance = new MiniSetup();
private MiniSetup()
{
}
public void EnsureInitialized(Context applicationContext)
{
if (MvxSimpleIoCContainer.Instance != null)
return;
var ioc = MvxSimpleIoCContainer.Initialize();
ioc.RegisterSingleton<IMvxTrace>(new MvxDebugOnlyTrace());
MvxTrace.Initialize();
var mockDispatcher = new SimpleDispatcher();
Ioc.RegisterSingleton<IMvxMainThreadDispatcher>(simpleDispatcher);
}
}
where SimpleDispatcher is something like:
public class SimpleDispatcher
: MvxMainThreadDispatcher
{
public readonly List<MvxViewModelRequest> Requests = new List<MvxViewModelRequest>();
public bool RequestMainThreadAction(Action action)
{
action();
return true;
}
}
If you want further MvvmCross functionality available (e.g. ShowViewModel navigation), then you'll need to provide further services - e.g. things like IMvxViewDispatcher - as the number of these increases, you might be better off just running through a full MvxSetup process (like your main app's Setup does)