Manually creating an HttpRequest for testing

HttpRequest.cs

// Whip up a fake HttpRequest
HttpRequest httpRequest = new HttpRequest("default.aspx", "http://www.diuturnal.com/default.aspx", string.Empty);

// Have to access the Headers collection first as this creates the internal collection we're about to hack
NameValueCollection headers = httpRequest.Headers;

// Accessing Headers property above will have created the private _headers member, so now we can grab it
headers = (NameValueCollection) httpRequest.GetType().GetField("_headers", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(httpRequest);

PropertyInfo readOnlyInfo = headers.GetType().GetProperty("IsReadOnly", BindingFlags.NonPublic | BindingFlags.Instance);

// Hack the collection to not be read-only then add some headers
readOnlyInfo.SetValue(headers, false, null);
headers["Accept"] = "text/xml,application/xml,application/xhtml+xml,text/html;
q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5";
headers["User-Agent"] = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.8.1.2) Gecko/20070219 Firefox/2.0.0.2";

// Finished hacking, set it back to read-only
readOnlyInfo.SetValue(headers, true, null);