只需模拟它以及任何其他依赖:

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);

你可能需要安装Microsoft.Extensions.Logging.Abstractions包来使用ILogger<T>。

此外，您可以创建一个真正的日志记录器:

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

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

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

只需模拟它以及任何其他依赖:

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);

你可能需要安装Microsoft.Extensions.Logging.Abstractions包来使用ILogger<T>。

此外，您可以创建一个真正的日志记录器:

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

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

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

如果还是实际的。简单的方法在。net core >= 3的测试中输出日志

[Fact]
public void SomeTest()
{
    using var logFactory = LoggerFactory.Create(builder => builder.AddConsole());
    var logger = logFactory.CreateLogger<AccountController>();
    
    var controller = new SomeController(logger);

    var result = controller.SomeActionAsync(new Dto{ ... }).GetAwaiter().GetResult();
}

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);

实际上，我找到了Microsoft.Extensions.Logging.Abstractions。NullLogger<>，这看起来像是一个完美的解决方案。安装包Microsoft.Extensions.Logging。抽象，然后按照示例配置和使用它:

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>();
    }
}

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);
}   

在@ivan-samygin和@stakx的基础上进一步构建，这里有一些扩展方法，它们也可以匹配Exception和所有日志值(KeyValuePairs)。

这些工作(在我的机器上;))与。net Core 3, Moq 4.13.0和Microsoft.Extensions.Logging.Abstractions 3.1.0。

/// <summary>
/// Verifies that a Log call has been made, with the given LogLevel, Message and optional KeyValuePairs.
/// </summary>
/// <typeparam name="T">Type of the class for the logger.</typeparam>
/// <param name="loggerMock">The mocked logger class.</param>
/// <param name="expectedLogLevel">The LogLevel to verify.</param>
/// <param name="expectedMessage">The Message to verify.</param>
/// <param name="expectedValues">Zero or more KeyValuePairs to verify.</param>
public static void VerifyLog<T>(this Mock<ILogger<T>> loggerMock, LogLevel expectedLogLevel, string expectedMessage, params KeyValuePair<string, object>[] expectedValues)
{
    loggerMock.Verify(mock => mock.Log(
        expectedLogLevel,
        It.IsAny<EventId>(),
        It.Is<It.IsAnyType>((o, t) => MatchesLogValues(o, expectedMessage, expectedValues)),
        It.IsAny<Exception>(),
        It.IsAny<Func<object, Exception, string>>()
        )
    );
}

/// <summary>
/// Verifies that a Log call has been made, with LogLevel.Error, Message, given Exception and optional KeyValuePairs.
/// </summary>
/// <typeparam name="T">Type of the class for the logger.</typeparam>
/// <param name="loggerMock">The mocked logger class.</param>
/// <param name="expectedMessage">The Message to verify.</param>
/// <param name="expectedException">The Exception to verify.</param>
/// <param name="expectedValues">Zero or more KeyValuePairs to verify.</param>
public static void VerifyLog<T>(this Mock<ILogger<T>> loggerMock, string expectedMessage, Exception expectedException, params KeyValuePair<string, object>[] expectedValues)
{
    loggerMock.Verify(logger => logger.Log(
        LogLevel.Error,
        It.IsAny<EventId>(),
        It.Is<It.IsAnyType>((o, t) => MatchesLogValues(o, expectedMessage, expectedValues)),
        It.Is<Exception>(e => e == expectedException),
        It.Is<Func<It.IsAnyType, Exception, string>>((o, t) => true)
    ));
}

private static bool MatchesLogValues(object state, string expectedMessage, params KeyValuePair<string, object>[] expectedValues)
{
    const string messageKeyName = "{OriginalFormat}";

    var loggedValues = (IReadOnlyList<KeyValuePair<string, object>>)state;

    return loggedValues.Any(loggedValue => loggedValue.Key == messageKeyName && loggedValue.Value.ToString() == expectedMessage) &&
           expectedValues.All(expectedValue => loggedValues.Any(loggedValue => loggedValue.Key == expectedValue.Key && loggedValue.Value == expectedValue.Value));
}