public void GetHighestIDReturnsOneMaxID()
        {
            var options = new DbContextOptionsBuilder <SGDB2Context>()
                          .UseInMemoryDatabase(databaseName: "SGDB2")
                          .Options;

            using (var context = new SGDB2Context(options))
            {
                var custID = StoreMethods.GetCustomerIDs(context);
                var result = StoreMethods.GetNewCustID(custID);
                Assert.IsType <int>(result);
            }
        }//8
        public void HighestIDSetsTo1IfListEmpty()
        {
            var options = new DbContextOptionsBuilder <SGDB2Context>()
                          .UseInMemoryDatabase(databaseName: "SGDB2")
                          .Options;

            using (var context = new SGDB2Context(options))
            {
                List <int> empty  = new List <int>();
                var        result = StoreMethods.GetNewCustID(empty);

                Assert.True(result == 1);
            }
        }//10
        public void GetHighestIDIncrements()
        {
            var options = new DbContextOptionsBuilder <SGDB2Context>()
                          .UseInMemoryDatabase(databaseName: "SGDB2")
                          .Options;

            using (var context = new SGDB2Context(options))
            {
                var custID = StoreMethods.GetCustomerIDs(context);
                var result = StoreMethods.GetNewCustID(custID);
                custID.Add(result);
                var result1 = StoreMethods.GetNewCustID(custID);

                Assert.True(result1 != result);
            }
        }//9