Can external components be used in bUnit ie. AntBlazor?

[gerickehoeksema]

I'm fairly new to Blazor, AntBlazor, and bUnit. I wanted to perform a cut but came across an issue where an AntBlazor component is throwing an exception when it needs to render although the service gets registered in the TextContext.
TestContext.Services.AddAntDesign();

This is the exception being thrown Object reference not set to an instance of an object. at AntDesign.Alert.OnAfterRenderAsync(Boolean firstRender)

This is the alert component
<Alert Type="@AlertType.Error" Message="Error text" Closable class="mb-3" />

When the external component doesn't need to render then the test passes.
My question would be, is there any additional setup that needs to happen to be able to successfully test AntBlazor components?

[linkdotnet]

Hey @gerickehoeksema

I am not an expert or user of AntBlazor myself, so this is just what I found out while browsing through their code.

Registering the service does not seem enough. You see the error because of this line taken from Alert.razor.cs:

protected override async Task OnAfterRenderAsync(bool firstRender)
{
    await base.OnAfterRenderAsync(firstRender);

    if (firstRender)
    {
        HtmlElement element = await JsInvokeAsync<HtmlElement>(JSInteropConstants.GetDomInfo, Ref);
        _height = element.ClientHeight;
    }
}

The JsInvoke will return a null element and therefore element.ClientHeight. will result in an NullReferenceException.
AntBlazor is providing a AntDesignTestContext you should inherit from. With that it should work.

[egil]

That's very cool they are including their own test context.

I do think a better solution for them (if this is supposed to be user facing) is to have an extension method on TestContext that does the needed set-up. Their users might be using different packages.