Omitting a call to `JSRuntimeInvocationHandler` during `JSInterop` set up causes test to not halt

[RiRiSharp]

Describe the bug

Set up a test for a call to a function which needs IJSRuntime, omit a call to JSRuntimeInvocationHandler. Normally one would add SetVoidResult(), SetCanceled() or SetException(ex). Then, the test does not halt with no indication of what is misconfigured.

Example:
Testing this component:

private async Task SomeFunction(IJSRuntime runTime)
{
    await runTime.InvokeVoidAsync("someFunction");
}

With this test:

[Fact]
public async Task ThisTestDoesNotHalt()
{
    // Arrange
    var ctx = new TestContext();
    ctx.JSInterop.SetupVoid("someFunction");
      
    // Act
    await SomeFunction(ctx.JSInterop.JSRuntime);
        
    // Assert
    _testOutputHelper.WriteLine("Halting test has succeeded");
}

Results in no output since this test does not halt.

Expected behavior:

I would expect the test to throw some exception or indicate in some other way that the framework is not able to handle such a set up.

Version info:

• bUnit version: 1.40
• .NET Runtime and Blazor version: .NET 9.0.7
• OS type and version: Windows 11 23H2

[linkdotnet]

Hey @RiRiSharp

I understand that it might be a bit weird and maybe we can discuss this. The docs shed a bit more light on that: https://bunit.dev/docs/test-doubles/emulating-ijsruntime.html#setting-up-invocations

Of course, we could just abort or throw after, let's say, 1 second, but maybe your code runs longer.
We can put some brainwork into this to ease the situation.

[RiRiSharp]

Hey, thanks for your reply. It was indeed after a second more thorough look at the docs that I found out what the issue was. I believe it is good to make something monkey proof, even in a testing scenario where we are testing whether the original code was monkey proof 😉 .

So, two solutions came to mind, which can also be combined:

1. A configurable timeout, quite like you suggested, something like JSInterop.SetupVoid("someFunction").ConfigureTimeout(TimeSpan.FromSeconds(10)), where the default timeout is some sensible value. I guess that one then would also want to be able to set the timeout globally like JSInterop.ConfigureTimeout(TimeSpan.FromSeconds(10)).
2. Using ITestOutputHelper (or some other way to output a warning/information message) to log something like This is taking quite long... perhaps you forgot to completely set up JSRuntimeInvocationHandler? Also after a sensible amount of time.

Let me know what you think!

I have to admit I do not quite understand yet what causes the 'hanging'. I understand that bUnit builds up a library JSRuntimeInvocations. So when a call is made to that library, and the specific value is not present, what happens then?

[linkdotnet]

Egil and will pick this up soon hopefully :)

The reason it hangs is because it is basically an unfinished task (TaskCompletionSource to be specific).
So the method just sets the result for that. If you don’t call that, your await inside your code will just never finish.

[RiRiSharp]

Let me know if there's something I can do, however small or big. Otherwise: good luck and thanks for making this library!

[RiRiSharp]

Can be closed, no? Or only when v2 is released?

[linkdotnet]

You are fast :D I will publish a pre-release version of v2 soon.

Technically v2 is not stable so let's keep it open and if you want you can try it. Feedback is always welcome

[linkdotnet]

Here you go: https://www.nuget.org/packages/bunit/2.0.47-preview

As said: This is the v2 preview package! You might encounter rough edges (hopefully not)

[linkdotnet]

Let's close this as we have it in v2 - in case of questions just reopen the ticket @RiRiSharp

[RiRiSharp]

Yes, perfect! I had some Saturday duties today, so hopefully I will be able to upgrade my reference to bUnit to the preview version tomorrow. Great work, thanks!

[RiRiSharp]

@linkdotnet This will be my final message on this issue: updating went smoothly, but v2.0.49-preview had the wrong obsoleteness message for TestContext, but I saw you already fixed that. The exception throwing works great and the message is informative 10/10

[linkdotnet]

Haha thanks for the feedback. Yeah don't just search and replace stuff throughout a codebase!!!! :D