var jsRuntimeMock = Mock.Create<IJSRuntime>(); Could not load file or assembly 'xunit.assert, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.'

[dwarwick]

I am creating a blazor unit test which involves a TelerikMaskedTextbox. I followed their guidance by creating the class located at

https://github.com/telerik/blazor-ui/blob/master/testing/bUnit-justmock/Telerik.Blazor.BUnit.JustMock/Common/TelerikTestContextWithActualRoot.cs

If I run the test, it passes just fine. If I debug the test, it crashes with the following error:

Could not load file or assembly 'xunit.assert, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.
at System.Reflection.RuntimeAssembly.InternalLoad(AssemblyName assemblyName, StackCrawlMark& stackMark, AssemblyLoadContext assemblyLoadContext, RuntimeAssembly requestingAssembly, Boolean throwOnFileNotFound)

Source "System.Private.CoreLib"

It crashes on the following line in the constructor

// mock the JS Interop service, you cannot use the one coming from the context
var jsRuntimeMock = Mock.Create<IJSRuntime>();

I am also occasionally seeing the following in the test output:

Bunit.JSRuntimeUnhandledInvocationException: bUnit's JSInterop has not been configured to handle the call:

    InvokeVoidAsync("mudElementRef.restoreFocus", Microsoft.AspNetCore.Components.ElementReference)

Configure bUnit's JSInterop to handle the call with following:

    SetupVoid("mudElementRef.restoreFocus", Microsoft.AspNetCore.Components.ElementReference)
or the following, to match any arguments:
    SetupVoid("mudElementRef.restoreFocus", _ => true)

The setup methods are available on an instance of the BunitJSInterop or
BunitJSModuleInterop type. The standard BunitJSInterop is available
through the TestContext.JSInterop property, and a BunitJSModuleInterop
instance is returned from calling SetupModule on a BunitJSInterop instance.

   at Bunit.BunitJSInterop.TryHandlePlannedInvocation[TValue](JSRuntimeInvocation invocation) in /_/src/bunit.web/JSInterop/BunitJSInterop.cs:line 83
   at Bunit.BunitJSInterop.HandleInvocation[TValue](JSRuntimeInvocation invocation) in /_/src/bunit.web/JSInterop/BunitJSInterop.cs:line 68
   at Bunit.JSInterop.Implementation.JSRuntimeExtensions.HandleInvokeAsync[TValue](BunitJSInterop jSInterop, String identifier, Object[] args) in /_/src/bunit.web/JSInterop/Implementation/JSRuntimeExtensions.cs:line 9
   at Bunit.JSInterop.BunitJSRuntime.InvokeAsync[TValue](String identifier, Object[] args) in /_/src/bunit.web/JSInterop/Implementation/BunitJSRuntime.cs:line 20
   at Microsoft.JSInterop.JSRuntimeExtensions.InvokeVoidAsync(IJSRuntime jsRuntime, String identifier, Object[] args)
   at MudBlazor.TaskExtensions.AndForget(Task task, TaskOption option)

Per the error message, I tried: adding JSInterop.SetupVoid("mudElementRef.restoreFocus", _ => true); as shown below

public TelerikTestContextWithActualRoot()
{
    JSInterop.Mode = JSRuntimeMode.Loose;
    JSInterop.SetupVoid("mudPopover.connect", _ => true);
    JSInterop.SetupVoid("mudElementRef.restoreFocus", _ => true);

    // mock the JS Interop service, you cannot use the one coming from the context
    var jsRuntimeMock = Mock.Create<IJSRuntime>();// This is Telerik.JustMock.Mock

    // you can also register a real one for actual localization to test that too
    var localizerMock = Mock.Create<ITelerikStringLocalizer>();
}

But I still get the same error.

I also tried installing the XUnit nuget package which did not help.

As I stated earlier, the passes if I just run it from the VS 2022 Test Explorer. I only see this error if I run the test in debug mode, which seems strange.

Any help would be appreciated.

[egil]

If you go about it as Telerik suggests and replace the IJSRuntime with a mock, the built-in handler for JSInterop in bUnit doesn't work anymore. I will ping the Telerik folks and see what can be done to make bUnits JSInterop work with their components.

I am not sure about the "Could not load file or assembly 'xunit.assert..." error you are seeing though, it may be something that @EdCharbeneau or one of the other folks from @telerik knows what's up with.

ps. edited your post's markdown a bit to make it more readable.

[dwarwick]

Thank you for your reply. Hopefully the Telerik folks can provide you with a solution. Thanks for editing my markdown.

[KristianMariyanov]

Hi, @dwarwick and @egil. I'm Kristian from the Blazor team. I will ping the colleagues from JustMock to see if they can help with the mock problem. @dwarwick, or @egil, did you try to use different mock tool, and can we confirm, that the exception is something related to the JustMock?
For the second exception:

Bunit.JSRuntimeUnhandledInvocationException: bUnit's JSInterop has not been configured to handle the call:

InvokeVoidAsync("mudElementRef.restoreFocus", Microsoft.AspNetCore.Components.ElementReference)

This call is not from our library, It looks like this is something related to MudBlazor. Is this something that you have installed in your project?

[egil]

@KristianMariyanov the second error is produced by our purpose-build mock/fake for JSInterop. It throws that error when it is in strict mode and tries to give a helpful error message telling the user what they can do to configure bUnits JSInterop mock to handle the call it is receiving.

Ideally, in your TelerikTestContextWithActualRoot example/classes ctor, you do not replace bUnits JSInterop/IJSRuntime with a mocked version. Instead, just configure it to handle the JavaScript calls your library is making.

[KristianMariyanov]

I just saw your suggestion and implement it.

@dwarwick you can see the latest version in the PR: telerik/blazor-ui#259.
Thanks, @dwarwick and @egil for bringing this to us. 🙏

[dwarwick]

Thanks to both of you.