public void Register_when_called_twice_with_same_task_name_throws()
 {
     ImgTaskFactoryRegistry.Register("test",
                                     (id, imgId, @params) => new TestConvertTask(Guid.NewGuid(), id, imgId, @params));
     Assert.Throws <ArgumentException>(() =>
                                       ImgTaskFactoryRegistry.Register("test",
                                                                       (id, imgId, @params) => new TestConvertTask(Guid.NewGuid(), id, imgId, @params)));
 }
 static TestConvertTask()
 {
     ImgTaskFactoryRegistry.Register("testConvert", (gid, imgId, @params) => new TestConvertTask(Guid.NewGuid(), gid, imgId, @params));
 }