public async void GetBalance_NotExistingClient_ThrowsException()
        {
            //Arrange
            var bl       = new BLClient(mockedReservationRepository, mockedClientRepository);
            var clientId = 5;

            //Act
            async Task act() => await bl.GetBalanceAsync(clientId);

            //Assert
            await Assert.ThrowsAsync <CustomException>(act);
        }
        public async void GetBalance_ClientWithReservations_AccountValuesGreaterThanZero() //MethodName_ScenarioDescription_ExpectedBehaviour
        {
            //Arrange
            var bl       = new BLClient(mockedReservationRepository, mockedClientRepository);
            var clientId = 10;

            //Act
            var balance = await bl.GetBalanceAsync(clientId);

            //Assert
            Assert.Equal(110, balance.DepositFeePaid);
            Assert.Equal(110, balance.CancellationFeePaid);
            Assert.Equal(110, balance.RentalFeePaid);
        }
        public async void GetBalance_ClientWithoutReservations_AccountValuesEqualToZero()
        {
            //Arrange
            var bl       = new BLClient(mockedReservationRepository, mockedClientRepository);
            var clientId = 20;

            //Act
            var balance = await bl.GetBalanceAsync(clientId);

            //Assert
            Assert.Equal(0, balance.DepositFeePaid);
            Assert.Equal(0, balance.CancellationFeePaid);
            Assert.Equal(0, balance.RentalFeePaid);
        }