单元测试-模拟ILogger返回null

时间:2020-09-02 08:47:24

标签: c# asp.net-core logging nunit moq

我有以下课程:

    public class UkFileHandler: FileHandler<UkFileHandler.FileMapper>
    {
        public class FileMapper : LookUpFieldDefinition
        {
            public int Name => 1;
            public int Address1 => 4;
            public int Address2 => 5;
        }

        public UkFileHandler(ILoggerFactory loggerFactory, IRecordParser recordParser, 
            IUnzipper unzipper, IFileStore fileStore, IRecordWriter writer) 
            : base(recordParser, unzipper, fileStore, writer)
        {
            Logger = loggerFactory.Create<UkFileHandler>();
        }

        protected override ILogger Logger { get; }

我正在尝试在单元测试中对此进行模拟,尝试如下:

  [Test]
        public void Test()
        {
            var mockLoggerFactory = new Mock<ILoggerFactory>();
            var mockedILogger = new Mock<ILogger>();
            mockLoggerFactory.Setup(lf=> lf.Create<UkFileHandler>()).Returns(mockedILogger.Object);

            var mockUnzipper = new Mock<IUnzipper>();
            var mockFileStore = new Mock<IFileStore>();
            var mockFileWriter = new Mock<IRecordWriter>();

            var mockFileHandler = new Mock<UkFileHandler>
                                    (mockLoggerFactory.Object, new RecordParser(mockLoggerFactory.Object),
                                    mockUnzipper.Object, mockFileStore.Object, mockFileWriter.Object);
           


            // commented out code which calls method 

            Assert.IsNotNull(result);
        }

我正在使用如下所示的自定义ILoggerFactory

 public interface ILoggerFactory
    { 
        ILogger Create<T>();
    }
}

我的问题是,在运行测试时,Logger实例为Null。我无法在这里错过任何东西的地方-有人可以帮忙吗?

2 个答案:

答案 0 :(得分:0)

问题是:

protected override ILogger Logger { get; }

在您的层次结构中,Logger属性是虚拟的或抽象的。但是有一个简单的解决方法。 只需将此吸气剂转换为UkFileHandler中的完整属性即可。像这样:

public class UkFileHandler: FileHandler<UkFileHandler.FileMapper>
{
    private readonly ILogger logger;
    
    public class FileMapper : LookUpFieldDefinition
    {
        public int Name => 1;
        public int Address1 => 4;
        public int Address2 => 5;
    }

    public UkFileHandler(ILoggerFactory loggerFactory, IRecordParser recordParser, 
        IUnzipper unzipper, IFileStore fileStore, IRecordWriter writer) 
        : base(recordParser, unzipper, fileStore, writer)
    {
        logger = loggerFactory.Create<UkFileHandler>();
    }

    protected override ILogger Logger => logger;
}

答案 1 :(得分:0)

第一个问题是,UkFileHandler是SUT吗?如果是这样,您通常不会嘲笑它。

它为空的原因是Logger属性是虚拟的或抽象的。您将在UkFileHandler中覆盖它,因此在继承层次结构中的某个位置将其标记为虚拟或抽象。完成后,即使您在构造函数中进行设置,Moq仍可以代理它并将其初始化为默认值(空)。

几种解决方法。

鉴于您在嘲笑一个实现,mockFileHandler.CallBase = true;将允许未明确设置的任何内容按照该实现工作。

另一种方法是设置Logger属性。由于受到保护,因此您必须执行以下操作:

mockFileHandler.Protected().Setup<ILogger>("Logger").Returns(mockedILogger.Object);