public void GetRentalByRentalIdReturnsRightRental()
{
//Arrange
IRentalRepository rentalRepository = Substitute.For <IRentalRepository>();
rentalRepository.GetRentalByRentalId(2).Returns(new Rental {
CustomerName = "Lars"
});
IUnitOfWork uow = Substitute.For <IUnitOfWork>();
uow.RentalRepository.Returns(rentalRepository);
RentalService rs = new RentalService(uow);
//Act
var rental = rs.GetRentalByRentalId(2);
//Assert
rental.CustomerName.Should().Be("Lars");
}