Button click throws Bunit.ElementNotFoundException

[nickmuller]

Describe the bug or question
Triggering a click event on a button results in a 'Bunit.ElementNotFoundException' exception. I have a form component with an edit button, after a click on the button it then is removed from the DOM. The form then shows a cancel and submit button. I can see that the click is being handled, so I think it's being referenced after being removed from DOM.

I've made a small project to reproduce the exception: XUnitTestProject1.zip

Example:
Testing this component:

<form>
    @if (State.IsReadonly)
    {
        <button class="editbutton" @onclick="EditHandler">Edit</button>
    }
    <div>
        @ChildContent
    </div>
    @if (!State.IsReadonly)
    {
        <button class="cancelbutton">Cancel</button>
        <button class="submitbutton">Submit</button>
    }
</form>

@code {
    [CascadingParameter] public FormState State { get; set; }
    [Parameter] public RenderFragment ChildContent { get; set; }

    private void EditHandler()
    {
        State.Edit();
    }
}

With this test:

public class UnitTest1 : TestContext
{
    [Fact]
    public void Test1()
    {
        var state = new FormState();
        var cut = RenderComponent<Form>(parameters => parameters
            .AddCascadingValue(state));

        cut.Find("button.editbutton").Click();

        Assert.False(cut.Instance.State.IsReadonly);
    }
}

Results in this output:

Bunit.ElementNotFoundException
Exception of type 'Bunit.ElementNotFoundException' was thrown.
   at Bunit.ElementFactory`1.AngleSharpWrappers.IElementFactory<TElement>.GetElement() in /_/src/bunit.web/Extensions/Internal/ElementFactory.cs:line 30
   at AngleSharpWrappers.Wrapper`1.get_WrappedElement()
   at AngleSharpWrappers.ElementWrapper.HasAttribute(String name)
   at Bunit.GeneralEventDispatchExtensions.TriggerEventAsync(IElement element, String eventName, EventArgs eventArgs) in /_/src/bunit.web/EventDispatchExtensions/GeneralEventDispatchExtensions.cs:line 49
   at Bunit.MouseEventDispatchExtensions.ClickAsync(IElement element, MouseEventArgs eventArgs) in /_/src/bunit.web/EventDispatchExtensions/MouseEventDispatchExtensions.cs:line 304
   at Bunit.MouseEventDispatchExtensions.Click(IElement element, Int64 detail, Double screenX, Double screenY, Double clientX, Double clientY, Int64 button, Int64 buttons, Boolean ctrlKey, Boolean shiftKey, Boolean altKey, Boolean metaKey, String type) in /_/src/bunit.web/EventDispatchExtensions/MouseEventDispatchExtensions.cs:line 286
   at XUnitTestProject1.UnitTest1.Test1

Expected behavior:
Click of the button should work without an error. As a workaround I now use cut.FindAll("button.editbutton")[0].Click();

Version info:

• Library version: v1.0.0-beta-11

[egil]

Ohh my.. two in one day. Thanks for reporting.

[egil]

I figured out the root cause and there is a fix on the way to the nightly channel now. I really appreciate the effort you put in to creating small repro samples. It makes my bug finding much easier. Thanks again!

[nickmuller]

Sure no problem!