public void ReturnTeamsInOrderOfGoalDifference() { //arrange List <MatchResult> matchResults = MatchResultsFixtures.GetChampionByGoalDifference(); var mockResultsRepository = new Mock <IMatchResultsRepository>(); mockResultsRepository.Setup(r => r.GetAll()).Returns(matchResults); //act var leagueTable = new LeagueTable(mockResultsRepository.Object); //assert Assert.AreEqual("Liverpool", leagueTable.GetWinningTeamName()); }