如何在ASP中使用ILogger进行单元测试。网络核心

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);
    }
}

正如你所看到的，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来测试和Moq来创建模拟和存根，我可以很容易地模拟DAO，但使用ILogger，我不知道该做什么，所以我只是传递null并注释掉运行测试时登录控制器的调用。是否有一种方法可以测试，但仍然以某种方式保存日志?

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());
    }
}

当前回答

更新(感谢@Gopal Krishnan的评论):

随着Moq >= 4.15.0，以下代码正在工作(不再需要强制转换):

 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);

之前版本的答案(Moq < 4.15.0):

对于使用Moq的。net core 3答案

https://stackoverflow.com/a/54646657/2164198 https://stackoverflow.com/a/54809607/2164198 https://stackoverflow.com/a/56728528/2164198

由于在ILogger.Log中的TState曾经是对象，现在是FormattedLogValues问题中描述的变化，不再工作

幸运的是，stakx提供了一个很好的解决方案。所以我把它贴出来，希望能帮别人节省时间(花了一段时间才弄明白):

 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);

2019-11-04 16:15:25

其他回答

当使用StructureMap / Lamar时:

var c = new Container(_ =>
{
    _.For(typeof(ILogger<>)).Use(typeof(NullLogger<>));
});

文档:

https://learn.microsoft.com/en-us/dotnet/api/microsoft.extensions.logging.abstractions.nulllogger?view=aspnetcore-2.1 http://structuremap.github.io/generics/

2018-10-03 12:19:48

这是一个通常放在静态helper类中的helper扩展方法:

static class MockHelper
{
    public static ISetup<ILogger<T>> MockLog<T>(this Mock<ILogger<T>> logger, LogLevel level)
    {
        return logger.Setup(x => x.Log(level, It.IsAny<EventId>(), It.IsAny<object>(), It.IsAny<Exception>(), It.IsAny<Func<object, Exception, string>>()));
    }

    private static Expression<Action<ILogger<T>>> Verify<T>(LogLevel level)
    {
        return x => x.Log(level, 0, It.IsAny<object>(), It.IsAny<Exception>(), It.IsAny<Func<object, Exception, string>>());
    }

    public static void Verify<T>(this Mock<ILogger<T>> mock, LogLevel level, Times times)
    {
        mock.Verify(Verify<T>(level), times);
    }
}

然后，你可以这样使用它:

//Arrange
var logger = new Mock<ILogger<YourClass>>();
logger.MockLog(LogLevel.Warning)

//Act

//Assert
logger.Verify(LogLevel.Warning, Times.Once());

当然，您可以轻松地将其扩展为模拟任何期望(即期望、消息等……)

更新。net 6与Moq 4.17.2 此扩展方法还允许使用正则表达式验证消息

static class MockHelper
{
    public static void VerifyLog<T>(this Mock<ILogger<T>> logger, LogLevel level, Times times, string? regex = null) =>
        logger.Verify(m => m.Log(
        level,
        It.IsAny<EventId>(),
        It.Is<It.IsAnyType>((x, y) => regex == null || Regex.IsMatch(x.ToString(), regex)),
        It.IsAny<Exception?>(),
        It.IsAny<Func<It.IsAnyType, Exception?, string>>()),
        times);
}

这就是如何使用它

logger.VerifyLog(LogLevel.Warning, Times.Exactly(2), "Simple match");
logger.VerifyLog(LogLevel.Warning, Times.Exactly(2), "[Yy]ou\scould do regex too.*");

2019-06-23 23:54:48

使用一个使用ITestOutputHelper(来自xunit)的自定义记录器来捕获输出和日志。下面是一个只将状态写入输出的小示例。

public class XunitLogger<T> : ILogger<T>, IDisposable
{
    private ITestOutputHelper _output;

    public XunitLogger(ITestOutputHelper output)
    {
        _output = output;
    }
    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func<TState, Exception, string> formatter)
    {
        _output.WriteLine(state.ToString());
    }

    public bool IsEnabled(LogLevel logLevel)
    {
        return true;
    }

    public IDisposable BeginScope<TState>(TState state)
    {
        return this;
    }

    public void Dispose()
    {
    }
}

在单元测试中使用它

public class BlogControllerTest
{
  private XunitLogger<BlogController> _logger;

  public BlogControllerTest(ITestOutputHelper output){
    _logger = new XunitLogger<BlogController>(output);
  }

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

2017-12-08 11:41:07

使用Telerik Just Mock创建记录器的模拟实例:

using Telerik.JustMock;
...
context = new XDbContext(Mock.Create<ILogger<XDbContext>>());

2020-06-29 19:12:23

最简单的解决方案是使用NullLogger。它是Microsoft.Extensions.Logging.Abstractions的一部分。

没有必要干扰工厂和其他不必要的建设。添加:

ILogger<BlogController> logger = new NullLogger<BlogController>();

2022-06-17 06:51:38

如何在ASP中使用ILogger进行单元测试。网络核心

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