ClaudeCodeExtension

Here’s the implementation for a `PaymentProcessor` class in your `ECommerceApp` project, including unit tests and a mock for the `IPaymentGateway` dependency. The extension generated this directly in your VS Code workspace with multi-line prompts and inline image attachments for the UI mockup.

```csharp
// PaymentProcessor.cs
using System;
using System.Threading.Tasks;
using Moq;

namespace ECommerceApp.Services
{
    public interface IPaymentGateway
    {
        Task<bool> ProcessPaymentAsync(decimal amount, string cardNumber);
    }

    public class PaymentProcessor
    {
        private readonly IPaymentGateway _paymentGateway;

        public PaymentProcessor(IPaymentGateway paymentGateway)
        {
            _paymentGateway = paymentGateway;
        }

        public async Task<PaymentResult> ProcessOrderAsync(Order order)
        {
            if (order.TotalAmount <= 0)
                return new PaymentResult(false, "Invalid order amount");

            var success = await _paymentGateway.ProcessPaymentAsync(
                order.TotalAmount, 
                order.PaymentDetails.CardNumber
            );

            return new PaymentResult(success, success ? "Payment successful" : "Payment failed");
        }
    }

    public record PaymentResult(bool Success, string Message);
}
```

```csharp
// PaymentProcessorTests.cs
using Xunit;
using Moq;

namespace ECommerceApp.Tests.Services
{
    public class PaymentProcessorTests
    {
        [Fact]
        public async Task ProcessOrderAsync_ValidOrder_ReturnsSuccess()
        {
            // Arrange
            var mockGateway = new Mock<IPaymentGateway>();
            mockGateway.Setup(g => g.ProcessPaymentAsync(100.50m, "4111111111111111"))
                      .ReturnsAsync(true);

            var processor = new PaymentProcessor(mockGateway.Object);
            var order = new Order(100.50m, new PaymentDetails("4111111111111111"));

            // Act
            var result = await processor.ProcessOrderAsync(order);

            // Assert
            Assert.True(result.Success);
            Assert.Equal("Payment successful", result.Message);
        }
    }
}
```

The extension also generated a UI mockup for the payment form (attached as an image) and suggested adding validation for card expiration dates. The entire workflow took 2 minutes from prompt to working code.