bUnit | testing library for Blazor components | Frontend Framework library

You aren't passing the new value into the Child component. This is one way you could make it work.

as far as I can tell, the component functions identically ...

That is correct. Task.Run(job) will run the job on the ThreadPool. In WebAssembly however there are no extra threads and the main (only) thread will have to run this job sooner or later.

In Blazor Server you do have Threads. Task.Run() will work there, but StateHasChanged() has to run on the main Thread. That means that

The reason why Inject doesn't infer the type of the instance but rather relies on the generic parameter is because it needs to enable scenarios where it is necessary to register values for base types or interfaces fixture.Inject(instance).

The way Inject works behind the scenes is that it delegates the registration to Register(Func creator) which then delegates it to a fixture.Customize(c => c.FromFactory(creator).OmitAutoProperties()). So you can see how it wouldn't work when you need type inference.

You could as you said, make registrations one by one, or you could implement your own injection. Note the implementation below is a lighter implementation of the builder that would be normally generated by AutoFixture, and should cover most scenarios. If you find that some features are not working, like seeded requests, you might need a more complete implementation of the injection.

A fallback service provider added to bUnit's root service provider is invoked if the root service provider cannot resolve a GetService request. With that info in mind, we can use Moq (or another mocking framework) and a little Reflection trickery to create a fallback service provider, which is really just something that implements the IServiceProvider interface, that will use Moq to create a mocked version of a requested service, when its GetService method is called.

This service provider will use Mock to create a mock of a requested service type once, and any subsequent requests will get the same type returned (they are saved in the mockedTypes dictionary).

The reason for this is that you can retrieve the same mocked instance of a type in both your test and in the component under test, which allows you to configure the mock in your test.

The GetMockedService extension method below makes it easy to pull out a Mock from the service provider.

I tried locally on my machine, and the test passed.

Here is a simplified version of your component, that only calls TimerElapsed_TickAsync one time per value change and not every time the timer runs out (AutoReset defaults to true), and two different ways to write the test that both pass on my machine:

The problem is that you are not rendering the component that actually does the rendering. Just passing in an IModalService doesn't do it.

My approach would be to create a mock of IModalService and assert that the expected method on it is called.

I just had to call:

bUnit allows you to perform multiple renders of a component under test. The first render will always have firstRender set to true, and any additional renders will have it set to false, just like the regular Blazor runtime.

For example:

Since AddTestAuthorization is an extension method, you need to use this to get to it. Its an unfortunate limitation in the C# language.

E.g.: