unittest-example-2

unittest-example-2.cs

// Interfaces
public interface IDatabase
    {
        Invoice GetInvoice(int invoiceId);
    }
    
  public interface IPrinter
    {
        void WriteLine(string text);
    }
    
     public interface IDateTimeWrapper
    {
        DateTime GetNow();
    }
    
    // Implementation 
    
    public class Database : IDatabase
    {
        public Invoice GetInvoice(int invoiceId)
        {
           // Code here ..
        }
    }
    
    public class Printer : IPrinter
    {
        public void WriteLine(string text)
        {
            throw new NotImplementedException();
        }
    }
    
    public class DateTimeWrapper : IDateTimeWrapper
    {
        public DateTime GetNow()
        {
            return DateTime.Now;
        }
    }