使用 Moq 模拟 HttpContext Response.Output

using System.IO;
using Moq;
using Xunit;

public class MyControllerTests
{
    [Fact]
    public void MyAction_WritesToResponseOutput()
    {
        // Arrange
        var httpContext = new Mock<HttpContext>();
        var response = new Mock<HttpResponse>();
        var output = new Mock<Stream>();

        httpContext.Setup(c => c.Response).Returns(response.Object);
        response.Setup(r => r.OutputStream).Returns(output.Object);

        var controller = new MyController()
        {
            ControllerContext = new ControllerContext()
            {
                HttpContext = httpContext.Object
            }
        };

        // Act
        controller.MyAction();

        // Assert
        output.Verify(s => s.Write(It.IsAny<byte[]>(), It.IsAny<int>(), It.IsAny<int>()), Times.Once());
    }
}