Mvx.Resolve fails in unit tests - unit-testing

I'm currently trying to write unit tests for an android/ios application written in xamaring using mvvmcross. I've followed the instructions in the wiki and they do work well to the point when a service tries to change the ViewModel this way:
var viewDispatcher = Mvx.Resolve<IMvxViewDispatcher>();
viewDispatcher?.ShowViewModel(
new MvxViewModelRequest(typeof(HomeViewModel), null, null, MvxRequestedBy.Unknown));
The tests fail at the first line with Mvx.Resolve();. I assume this is down to registering the interfaces in the mock IoC container:
this.mockDispatcher = new MockDispatcher();
this.Ioc.RegisterSingleton<IMvxViewDispatcher>(this.mockDispatcher);
this.Ioc.RegisterSingleton<IMvxMainThreadDispatcher(this.mockDispatcher);
so Mvx cannot resolve then when called this way. Can this code be tested or is there any other possibility to change the ViewModel from the service?

I think your AdditionalSetup never gets called. You have to add the SetUp attribute to a setup method and call the Setup() of MvxIoCSupportingTest if you use nunit, else the respective attribute.
public abstract class MvxTestBase : MvxIoCSupportingTest
{
protected MockDispatcher mockDispatcher;
protected override void AdditionalSetup()
{
this.mockDispatcher = new MockDispatcher();
this.Ioc.RegisterSingleton<IMvxViewDispatcher>(this.mockDispatcher);
this.Ioc.RegisterSingleton<IMvxMainThreadDispatcher>(this.mockDispatcher);
}
[SetUp]
public virtual void SetupTest()
{
Setup();
}
}
Or you call it in each test as shown here: https://mvvmcross.com/docs/testing#section-test-class-declaration-and-setup

Related

ASP.NET Web API Unit Test Autofac Module with BuildManager.GetReferencedAssemblies()

Working on a project in ASP.NET Web API 2 which has Autofac as my IoC container. This project is hosted on IIS and in my Autofac module I use the following method to scan for assemblies:
var asm = BuildManager.GetReferencedAssemblies().Cast<Assembly>().ToArray();
Why?
https://docs.autofac.org/en/latest/register/scanning.html#iis-hosted-web-applications
But now we are making Unit Tests using NUnit, during my setup I register my module which uses this method. Now I receive the following exception when running my tests:
System.InvalidOperationException: 'This method cannot be called during the application's pre-start initialization phase.'
I understand why I have this exception but I don't have a clue how to make my code work in tests and for deployment environments.
Setup method of NUnit:
[TestFixture]
public abstract class ApplicationTestBase
{
[SetUp]
public override void Init()
{
var builder = new ContainerBuilder();
// If the class requires auto mapper mapping, initialize them
// We do this in order not to init them for every test => optimalisation!
if (GetType().GetCustomAttributes<RequiresAutoMapperMappingsAttribute>(false) != null)
{
builder.RegisterModule<AutoMapperModule>();
}
this.Container = builder.Build();
}
}
Do I need to create a new module specific for my Unit tests or is there another way for this?
AutoMapperTest
[RequiresAutoMapperMappings]
[TestFixture]
public class AutoMapperTests : ApplicationTestBase
{
[Test]
public void Assert_Valid_Mappings()
{
Mapper.AssertConfigurationIsValid();
}
}
UPDATE
Like Cyril mentioned: Why do you need Ioc in your unit tests? I went searching and indeed you don't have to use the Ioc in your tests. So I ditched the Ioc and initialized my mapper configuration byy doing:
Mapper.Initialize(configuration =>
{
var asm = AppDomain.CurrentDomain.GetAssemblies()
.Where(a => a.FullName.StartsWith("ProjectWebService."));
configuration.AddProfiles(asm);
});
I would recommend separating the "how to load assemblies" logic from the "do assembly scanning and register modules logic."
Right now I'm guessing you have something like this all in one method.
public IContainer BuildContainer()
{
var asm = BuildManager.GetReferencedAssemblies().Cast<Assembly>().ToArray();
var builder = new ContainerBuilder();
builder.RegisterAssemblyTypes(asm);
var container = builder.Build();
}
Not exactly that, but something similar - the loading of assemblies is inlined and directly used.
Separate that so you can swap that logic in for testing. For example, consider allowing a parameter to be optionally passed so you can override the logic in test.
public IContainer BuildContainer(Func<IEnumerable<Assembly>> assemblyLoader = null)
{
IEnumerable<Assembly> asm = null;
if (assemblyLoader != null)
{
asm = assemblyLoader();
}
else
{
asm = BuildManager.GetReferencedAssemblies().Cast<Assembly>().ToArray();
}
var builder = new ContainerBuilder();
builder.RegisterAssemblyTypes(asm);
var container = builder.Build();
}
Your default logic will work the way you want, but then in testing you can swap in something else.
var container = BuildContainer(() => AppDomain.GetAssemblies());
There are lots of ways you can do that swap-in. It could be anything from a static property you can set somewhere to a virtual method you can override somewhere. The point is, by separating the assembly loading logic you can get the test-time behavior to work but still use the registration behavior you're after.

How to mock this callback using Mockito?

I have this production code in my Presenter:
#UiThread
public void tryToReplaceLogo(String emailInitiallySearchedFor, String logoUrl) {
if(isTheEmailWeAskedApiForStillTheSameAsInTheInputField(emailInitiallySearchedFor)){
if (!TextUtils.isEmpty(logoUrl)) {
downloadAndShowImage(logoUrl);
} else {
view.displayDefaultLogo();
}
}
}
public void downloadAndShowImage(String url) {
final Target target = new Target() {
#Override
public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
view.displayLogoFromBitmap(bitmap);
}
#Override
public void onBitmapFailed(Drawable errorDrawable) {
}
#Override
public void onPrepareLoad(Drawable placeHolderDrawable) {
}
};
Picasso.with(view.getViewContext()).load(url).resize(150, 150).centerInside().into(target);
}
And this unit test for it:
#Test
public void testDisplayLogoIfValidUrlReturnedAndEmailEnteredIsTheSame() throws Exception {
when(loginView.getUserName()).thenReturn(VALID_EMAIL);
when(loginView.getViewContext()).thenReturn(context);
loginLogoFetcherPresenter.onValidateEmailEvent(createSuccessfulValidateEmailEvent(VALID_EMAIL));
waitForAsyncTaskToKickIn();
verify(loginView).displayLogoFromBitmap((Bitmap) anyObject());
}
However, the displayLogoFromBitmap method is never called so my test fails. I need to mock the Target dependency to invoke the onBitmapLoaded method but I don't know how.
Possibly I need to create a static inner class that implements Target so that I can set a Mocked implementation of that in my tests, but how do I invoke the onBitmapLoaded method on the mock?
EDIT:
I have a setter field for Picasso in my LoginPresenter now. In production, (as I am using AndroidAnnotations), I instantiate it in
#AfterInject
void initPicasso() {
picasso = Picasso.with(context):
}
In my test, I mock Picasso like so:
#Mock
Picasso picasso;
#Before
public void setUp() {
picasso = mock(Picasso.class, RETURNS_DEEP_STUBS);
}
(I don't remember why, but I can't use Mockito 2 at this point. It was some incompatibility with something, I think)
In my test case, I got to this point and I don't know what to do:
#Test
public void displayLogoIfValidUrlReturnedAndEmailEnteredIsTheSame() throws Exception {
when(loginView.getUserName()).thenReturn(VALID_EMAIL);
when(loginView.getViewContext()).thenReturn(context);
when(picasso.load(anyString()).resize(anyInt(), anyInt()).centerInside().into(???)) // What do I do here?
loginLogoFetcherPresenter.onValidateEmailEvent(createSuccessfulValidateEmailEvent(VALID_EMAIL));
waitForAsyncTaskToKickIn();
verify(loginView).displayLogoFromBitmap((Bitmap) anyObject());
}
I need to mock the Target dependency
No; do not mock the system under test. Target is as much a part of that system as anything; you wrote the code for it, after all. Remember, once you mock out a class, you commit to not using its implementation, so trying to mock Target to invoke onBitmapLoaded is missing the point.
What's going on here is that you're passing Target—which is real code you wrote that is worth testing—into Picasso, which is external code you didn't write but do depend on. This makes Picasso the dependency worth mocking, with the caveat that mocking interfaces you don't control can get you into trouble if they change (e.g. a method turns final).
So:
Mock your Picasso instance, and the RequestCreator instance Picasso returns when it loads. RequestCreator implements the Builder pattern, so it's a prime candidate for Mockito 2.0's RETURNS_SELF option or other Builder pattern strategies.
Pass the Picasso instance into your system under test, rather than creating it using Picasso.with. At this point you may not need to stub LoginView.getViewContext(), which is a good thing as your test can interact less with hard-to-test Android system classes, and because you've further separated object creation (Picasso) from business logic.
Use an ArgumentCaptor in your test to extract out the Target method that was called on RequestCreator.into.
Test the state of the system before the async callback returns, if you'd like. It's optional, but it's definitely a state your system will be in, and it's easy to forget to test it. You'd probably call verify(view, never()).onBitmapLoaded(any()).
Call target.onBitmapLoaded yourself. You have the target instance at this point, and it should feel correct to explicitly call your code (that is written in your system-under-test) from your test.
Assert your after-callback state, which here would be verify(view).onBitmapLoaded(any()).
Note that there is an existing test helper called MockPicasso, but it seems to require Robolectric, and I haven't reviewed its safety or utility myself.

Mock SomeClass.getClassLoader() when called in method (Mockito / PowerMockito)

I have inherited some code that isn't tested and which loads a resource using a method like :
SomeClass.class.getClassLoader().getResource("somefile");
I've written the following test but there are 0 interactions with the Mock class loader I've created. Can anyone comment on whether this type of test is possible.
public enum SomeClass {
INSTANCE;
public boolean someMethod() {
URL pathToLicense = SomeClass.class.getClassLoader().getResource("somefile");
return false;
}
}
#Test
public void testLicenseWorkflow(){
ClassLoader cl = PowerMockito.mock(ClassLoader.class);
File f = new File("someFile");
assertTrue(f.exists());
logger.info(f.getCanonicalPath() );
when(cl.getResource("somefile")).thenReturn(f.toURL());
verify(cl).getResource("somefile");
assertTrue(SomeClass.INSTANCE.someMethod());
}
Update - Adding a resources via Classloader
I've also tried the following but the someMethod this doens't seem to work either
new URLClassLoader(((URLClassLoader) SomeClass.INSTANCE.getClass().getClassLoader()).getURLs()) {
#Override
public void addURL(URL url) {
super.addURL(url);
logger.info("Calling add URL");
}
}.addURL(f.toURI().toURL());
You are not passing cl to anything. You prepare a mock for a classloader but then proceed to load the resource with another classloader, the one that loaded SomeClass. That is why you have 0 interactions in your mock.
And about your first question, it is possible if somehow you pass your mocked classloader to the method that actually loads the resource. For example, something like
public boolean someMethod(Classloader loader) {
URL pathToLicense = loader.getResource("somefile");
return false;
}
But I have to say that IMO, this test is not very useful, you should be mocking your own components, not java classes. If your goal mocking the classloader is to inject a different file when testing, a better approach is to change your code to receive a Stream and inject a stream connected to the file in production and in testing inject a stream connected to an element in memory.
In other words, resources make for bad testing when they need to be changed at test time

Need help testing Binding in Windows Phone 8

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.
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)

Unit testing - should I use mocks or make private method more visible

I'm looking for some design advice for a new module of the application I am working on, particularly with regards to how to make the design testable.
The problem is very common - load some data from a database, run some operations against the data, and save the result to the database. Most other modules in the application have the following pattern:
private repo; //Set in constructor
public void Run()
{
Stuff stuff = repo.LoadStuff()
Result result = RunOperationsInPrivateMethod(stuff); //private method
repo.SaveResult(result);
}
So to test this, I see that I have a couple of choices:
Inject a mock repo that I can use to return a Stuff and verify a Result.
Refactor RunOperationsInPrivateMethod to protected access, and test
the operations directly.
Am I missing any other options? What are peoples preferences?
In general, don't test private methods, instead, think whether your private method really should be a public method of another class. ie, decompose your object into smaller objects with focused functionality.
eg, perhaps Run should be
private repo; //Set in constructor
private IOperation operation; // injected in constructor or through dependency injection.
public void Run()
{
Stuff stuff = repo.LoadStuff()
Result result = operation.Run(stuff); //private instance with public method
repo.SaveResult(result);
}
then Run would be a public method of an operations class
class SecretOperation : IOperation
{
public void Run(Stuff stuff) { /* secret stuff */ }
}
Then also, you wouldn't have to load a Stuff from a database to test, just create a stuff in a fixture focused on testing SecretOperation. Now your unit tests can be more focused.