unittest-example-4

unittest-example-4.cs

    
    // PrintInvoiceCommand Class
    
    public class PrintInvoiceCommand
    {
        private readonly IDatabase _database;
        private readonly IPrinter _printer;

        public PrintInvoiceCommand(
            IDatabase database,
            IPrinter printer)
        {
            _database = database;
            _printer = printer;
        }

        public void Execute(int invoiceId)
        {
            var invoice = _database.GetInvoice(invoiceId);

            var writer = new InvoiceWriter(_printer, invoice);

            writer.Write();
        }
    }
    
    // InvoiceWriter Class
    
    public class InvoiceWriter
    {
        private readonly IPrinter _printer;
        private readonly Invoice _invoice;

        public InvoiceWriter(
            IPrinter printer, 
            Invoice invoice)
        {
            _printer = printer;
            _invoice = invoice;

            _printer.SetPageLayout(new PageLayout());

            if (_invoice.IsOverdue)
                _printer.SetInkColor("Red");
        }

        public void Write()
        {
            _printer.WriteLine("Invoice ID: " + _invoice.Id);

            // Remaining print statements would go here
        }
    }