public async Task GetAllSeasonsAsKeyValuePairs()
        {
            var countriesList = new List <Country>
            {
                new Country {
                    Id = 1, Name = "England"
                }
            };
            var championshipsList = new List <Championship> {
                new Championship {
                    Id = 1, Name = "Premier League"
                }
            };
            var seasonsList = new List <Season>();

            var mockCountryRepo = new Mock <IRepository <Country> >();

            mockCountryRepo.Setup(r => r.All()).Returns(countriesList.AsQueryable());

            var mockChampionshipRepo = new Mock <IRepository <Championship> >();

            mockChampionshipRepo.Setup(r => r.All()).Returns(championshipsList.AsQueryable());
            mockChampionshipRepo.Setup(r => r.Get(It.IsAny <int>())).Returns <int>(id => championshipsList.FirstOrDefault(c => c.Id == id));

            var mockSeasonRepo = new Mock <IRepository <Season> >();

            mockSeasonRepo.Setup(r => r.All()).Returns(seasonsList.AsQueryable());
            mockSeasonRepo.Setup(r => r.AddAsync(It.IsAny <Season>())).Callback <Season>(season => seasonsList.Add(new Season
            {
                Id           = 1,
                Name         = season.Name,
                Championship = season.Championship
            }));

            var seasonService = new SeasonService(mockSeasonRepo.Object, mockChampionshipRepo.Object);

            var firstSeasonViewModel = new SeasonViewModel
            {
                Name               = "2020/21",
                ChampionshipId     = 1,
                ChampionshipsItems = new ChampionshipService(
                    mockChampionshipRepo.Object,
                    mockCountryRepo.Object)
                                     .GetAllAsKeyValuePairs()
            };

            var secondSeasonViewModel = new SeasonViewModel
            {
                Name           = "2021/22",
                ChampionshipId = 1
            };

            await seasonService.CreateAsync(firstSeasonViewModel);

            await seasonService.CreateAsync(secondSeasonViewModel);

            var keyValuePairs = seasonService.GetAllAsKeyValuePairs().ToList();

            Assert.True(keyValuePairs.Count == 2);
            Assert.True(firstSeasonViewModel.ChampionshipsItems.Count() == 1);
        }