unittest-example-3

unittest-example-3.cs

[TestFixture]
    public class PrintInvoiceCommandTests
    {
    // Define the needed class and it's dependencies mocks
        private PrintInvoiceCommand _command;
        private Mock<IDatabase> _mockDatabase;
        private Mock<IPrinter> _mockPrinter;
        private Mock<IDateTimeWrapper> _mockDateTime;
        private Invoice _invoice;
    
    // Define the constants that we will use when setup the mocks
        private const int InvoiceId = 1;
        private const decimal Total = 1.23m;
        private static readonly DateTime Date = new DateTime(2001, 2, 3);

        [SetUp]
        public void SetUp()
        {
            _invoice = new Invoice()
            {
                Id = InvoiceId,
                Total = Total
            };

            _mockDatabase = new Mock<IDatabase>();
            _mockPrinter = new Mock<IPrinter>();
            _mockDateTime = new Mock<IDateTimeWrapper>();
            
            // Setup the mocks behaviours
            _mockDatabase
                .Setup(p => p.GetInvoice(InvoiceId))
                .Returns(_invoice);

            _mockDateTime
                .Setup(p => p.GetNow())
                .Returns(Date);

            _command = new PrintInvoiceCommand(
                _mockDatabase.Object,
                _mockPrinter.Object,
                _mockDateTime.Object);
        }

        [Test]
        public void TestExecuteShouldPrintInvoiceNumber()
        {
        // Here we will called execute(...) then we will verify if the  p.WriteLine("Invoice ID: 1") is called once and the invoice id is = 1
            _command.Execute(InvoiceId);

            _mockPrinter
                .Verify(p => p.WriteLine("Invoice ID: 1"),
                    Times.Once);
        }

        [Test]
        public void TestExecuteShouldPrintTotalPrice()
        {
            _command.Execute(InvoiceId);

            _mockPrinter
                .Verify(p => p.WriteLine("Total: $1.23"),
                    Times.Once);
        }

        [Test]
        public void TestExecuteShouldPrintTodaysDate()
        {
            _command.Execute(InvoiceId);

            _mockPrinter
                .Verify(p => p.WriteLine("Printed: 2/3/2001"),
                    Times.Once);
        }
    }