Tests.cs

public class ShipmentTests
{
    [Fact]
    public void Shipment_CanShip_ReturnsTrue_WhenAllRulesPass()
    {
        // Arrange
        var shipment = new ShipmentBuilder()
            .WithDestination("New York")
            .WithStatus(ShipmentStatus.Pending)
            .WithPackedPackages(3)
            .Build();

        var rules = new List<IShipmentReadinessRule>
        {
            new HasValidDestinationRule(),
            new AllPackagesPackedRule(),
            new NotAlreadyShippedRule()
        };

        // Act
        var result = shipment.CanShip(rules);

        // Assert
        Assert.True(result);
    }

    [Fact]
    public void Shipment_CanShip_ReturnsFalse_WhenAnyRuleFails()
    {
        // Arrange
        var shipment = new ShipmentBuilder()
            .WithDestination("") // Invalid
            .WithStatus(ShipmentStatus.Pending)
            .WithPackedPackages(3)
            .Build();

        var rules = new List<IShipmentReadinessRule>
        {
            new HasValidDestinationRule(),
            new AllPackagesPackedRule(),
            new NotAlreadyShippedRule()
        };

        // Act
        var result = shipment.CanShip(rules);

        // Assert
        Assert.False(result);
    }
}