public void ONSPostcodeExistsMeetsExpectation(string candidate, bool expectation)
        {
            var onsPostcodes = new List <IONSPostcode>()
            {
                new ONSPostcode
                {
                    Postcode = "abc"
                },
                new ONSPostcode
                {
                    Postcode = "def"
                },
                new ONSPostcode
                {
                    Postcode = "ghi"
                }
            };

            // arrange
            var externalDC = new Mock <IExternalDataCache>();

            externalDC
            .SetupGet(rdc => rdc.ONSPostcodes)
            .Returns(onsPostcodes);

            var sut = new PostcodesDataService(externalDC.Object);

            // act
            var result = sut.ONSPostcodeExists(candidate);

            // assert
            Assert.Equal(expectation, result);
        }
        public void PostcodeExistsMeetsExpectation(string candidate, bool expectation)
        {
            // arrange
            var externalDC = new Mock <IExternalDataCache>();

            externalDC
            .SetupGet(rdc => rdc.Postcodes)
            .Returns(new HashSet <string>()
            {
                "abc", "def", "ghi"
            });

            var sut = new PostcodesDataService(externalDC.Object);

            // act
            var result = sut.PostcodeExists(candidate);

            // assert
            Assert.Equal(expectation, result);
        }