如何在ASP中使用ILogger进行单元测试。网芯

Question

这是我的控制器：

public class BlogController : Controller
{
    private IDAO<Blog> _blogDAO;
    private readonly ILogger<BlogController> _logger;

    public BlogController(ILogger<BlogController> logger, IDAO<Blog> blogDAO)
    {
        this._blogDAO = blogDAO;
        this._logger = logger;
    }
    public IActionResult Index()
    {
        var blogs = this._blogDAO.GetMany();
        this._logger.LogInformation("Index page say hello", new object[0]);
        return View(blogs);
    }
}

如你所见，我有两个依赖项，一个IDAO和一个ILogger

这是我的测试类，我使用xUnit进行测试，使用Moq创建mock和stub，我可以轻松地模拟DAO，但使用ILogger我不知道该怎么做，所以在运行测试时，我只传递null并注释掉登录控制器的调用。有没有一种方法可以进行测试，但仍然以某种方式保留记录器？

public class BlogControllerTest
{
    [Fact]
    public void Index_ReturnAViewResult_WithAListOfBlog()
    {
        var mockRepo = new Mock<IDAO<Blog>>();
        mockRepo.Setup(repo => repo.GetMany(null)).Returns(GetListBlog());
        var controller = new BlogController(null,mockRepo.Object);

        var result = controller.Index();

        var viewResult = Assert.IsType<ViewResult>(result);
        var model = Assert.IsAssignableFrom<IEnumerable<Blog>>(viewResult.ViewData.Model);
        Assert.Equal(2, model.Count());
    }
}

Answer 1

更新（感谢@Gopal Krishnan的评论）：

用最小起订量

 loggerMock.Verify(
                x => x.Log(
                    LogLevel.Information,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>((o, t) => string.Equals("Index page say hello", o.ToString(), StringComparison.InvariantCultureIgnoreCase)),
                    It.IsAny<Exception>(),
                    It.IsAny<Func<It.IsAnyType, Exception, string>>()),
                Times.Once);

以前版本的答案（对于Moq

对于使用最小起订量的net core 3答案

• https://stackoverflow.com/a/54646657/2164198

由于ILogger中的问题TState中描述的更改，不再工作。日志以前是对象，现在格式化为LogValues

幸运的是，stakx提供了一个不错的解决方案。所以我把它贴出来，希望它能为其他人节省时间（花了一段时间才弄清楚）：

 loggerMock.Verify(
                x => x.Log(
                    LogLevel.Information,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>((o, t) => string.Equals("Index page say hello", o.ToString(), StringComparison.InvariantCultureIgnoreCase)),
                    It.IsAny<Exception>(),
                    (Func<It.IsAnyType, Exception, string>) It.IsAny<object>()),
                Times.Once);

Answer 2

实际上，我已经找到了微软。扩展。登录中。抽象。空记录器

using Microsoft.Extensions.Logging;

public void ConfigureServices(IServiceCollection services)
{
    ...

    services.AddSingleton<ILoggerFactory, NullLoggerFactory>();

    ...
}

using Microsoft.Extensions.Logging;

public class MyClass : IMyClass
{
    public const string ErrorMessageILoggerFactoryIsNull = "ILoggerFactory is null";

    private readonly ILogger<MyClass> logger;

    public MyClass(ILoggerFactory loggerFactory)
    {
        if (null == loggerFactory)
        {
            throw new ArgumentNullException(ErrorMessageILoggerFactoryIsNull, (Exception)null);
        }

        this.logger = loggerFactory.CreateLogger<MyClass>();
    }
}

和单元测试

//using Microsoft.VisualStudio.TestTools.UnitTesting;
//using Microsoft.Extensions.Logging;

[TestMethod]
public void SampleTest()
{
    ILoggerFactory doesntDoMuch = new Microsoft.Extensions.Logging.Abstractions.NullLoggerFactory();
    IMyClass testItem = new MyClass(doesntDoMuch);
    Assert.IsNotNull(testItem);
}   

Answer 3

只要把它和任何其他依赖性都模仿一下：

var mock = new Mock<ILogger<BlogController>>();
ILogger<BlogController> logger = mock.Object;

//or use this short equivalent 
logger = Mock.Of<ILogger<BlogController>>()

var controller = new BlogController(logger);

您可能需要安装Microsoft。扩展。登录中。摘要要使用的包ILogger

此外，您可以创建一个真正的记录器：

var serviceProvider = new ServiceCollection()
    .AddLogging()
    .BuildServiceProvider();

var factory = serviceProvider.GetService<ILoggerFactory>();

var logger = factory.CreateLogger<BlogController>();