public async Task <ActionResult <Domain.Models.Car> > Get(string regNo)
        {
            var query = new CarByRegNo(regNo);
            var car   = await query.Execute(_dbSource);

            return(Ok(car));
        }
        public async Task ShouldReturnNotNull()
        {
            var dbDataAccess = Substitute.For <IDbDataAccess>();

            dbDataAccess
            .Query(Arg.Any <Expression <Func <DataAccess.Entities.Car, bool> > >(), Arg.Any <Expression <Func <DataAccess.Entities.Car, Domain.Models.Car> > >())
            .Returns(new[] { new Domain.Models.Car("GLW975", "Volvo", "V60", 2016) });

            var sut = new CarByRegNo("GLW975");

            var car = await sut.Execute(dbDataAccess);

            car.Should().NotBeNull();
        }