public void GetCountryExtension_ReturnsPhoneNumberExtension() { //Arrange var countries = new List <CountryIdentifiers> { new CountryIdentifiers() { CountryId = 1, CountryCode = "NZ", PhoneExtension = "64" }, new CountryIdentifiers() { CountryId = 2, CountryCode = "AU", PhoneExtension = "61" } }.AsQueryable(); string countryCode = "NZ"; string phoneExtension = "64"; var mockSet = new Mock <DbSet <CountryIdentifiers> >(); mockSet.As <IQueryable <CountryIdentifiers> >().Setup(m => m.Provider).Returns(countries.Provider); mockSet.As <IQueryable <CountryIdentifiers> >().Setup(m => m.Expression).Returns(countries.Expression); mockSet.As <IQueryable <CountryIdentifiers> >().Setup(m => m.ElementType).Returns(countries.ElementType); mockSet.As <IQueryable <CountryIdentifiers> >().Setup(m => m.GetEnumerator()).Returns(countries.GetEnumerator()); var mockContext = new Mock <StudentContext>(); mockContext.Setup(c => c.CountryIdentifiers).Returns(mockSet.Object); //Act var repo = new CountryIdentifiersRepository(mockContext.Object); var results = repo.GetCountryExtension(countryCode); //Assert Assert.AreEqual("64", results); }