public void QuestionFind_returns_null_question_if_is_unavailable()
{
var firstQuestion = new Question { Id = 1, SurveyId = 1 };
var questionsRepository = new InMemoryQuestionsRepository();
questionsRepository.Create(firstQuestion);
var nextQuestion = new QuestionFinder(questionsRepository).FindNext(firstQuestion.Id);
Assert.That(nextQuestion, Is.Null);
}