public async void AddRemoveHandlerRegistry()
{
CreateMessageContext();
var document = DomOperationsTesting.CreateDocument();
var x = new MessageRegistry(document);
var counter = 0;
Task Handler(MessageEventArgs args)
{
counter++;
return(Task.CompletedTask);
}
x.Add("a", Handler);
await document.Head.NotifyEvent("_a");
Assert.Equal(1, counter);
x.Remove("b", Handler);
await document.Head.NotifyEvent("_a");
Assert.Equal(2, counter);
x.Remove("a", Handler);
await document.Head.NotifyEvent("_a");
Assert.Equal(2, counter);
}