public void GetEpisodeIdWorksCorrectly() { var episodes = new List <Episode>(); var episode = new Episode() { Id = "test", Webtoon = new Webtoon() { TitleNumber = "123" }, EpisodeNumber = "456" }; episodes.Add(episode); var mockEpisodesRepo = new Mock <IEpisodesRepository>(); mockEpisodesRepo.Setup(x => x.All()).Returns(episodes.AsQueryable()); var service = new EpisodesService(null, mockEpisodesRepo.Object, null, null, null, null, null, null); var result = service.GetEpisodeId("123", "456"); Assert.Equal("test", result); }