public void Ping_throws_exception_on_empty_parameters()
{
var uri = new Uri("http://google.com");
Assert.Throws<ArgumentNullException>(() => this.pingbackService.SendPingback(null, uri, uri));
Assert.Throws<ArgumentNullException>(() => this.pingbackService.SendPingback(uri, null, uri));
Assert.Throws<ArgumentNullException>(() => this.pingbackService.SendPingback(uri, uri, null));
}