No creator found for com.gargoylesoftware.htmlunit.UnexpectedPage (JSON response)

[ashes999]

I'm trying to write a functional test for an MVC5 + Web API project where I log in (via web forms), and then make a POST call directly to the API route. When I make the call to client.GetPage, I get an InvalidOperationException with this message: No creator found for com.gargoylesoftware.htmlunit.UnexpectedPage

This was reported against HtmlUnit itself on SO about five years ago.

var client = new WebClient(BrowserVersion.CHROME);
 var method = new HttpMethod(com.gargoylesoftware.htmlunit.HttpMethod.POST);
var json = JsonConvert.SerializeObject(inputObject);

var webRequest = new WebRequest(new java.net.URL("http://localhost/site/api/game"), new HttpMethod(method))
{
    RequestBody = "=" + json // WebAPI expects this. Don't ask me why.
};
var page = client.GetPage(webRequest);

I can see the call hit the server side (including the response object which comes back) -- it's not throwing an exception there, only on the client. The response is pure JSON:

{
    "Data": [
        {
            "Id": "00000000-0000-0000-0000-000000000000",
            "Name": "FT-FunctionalTestGame",
            "OwnerId": 3
        }
    ],
    "Errors": null
}

[asbjornu]

I wouldn't expect this project to receive an update before IKVM is ported to .NET Core. See #35 for details.