System.ArgumentNullException : Value cannot be null. (Parameter 'logger')

Priya

1194 Points

33 Posts

I'm using xUnit test for unit testing and trying to test the api endpoints. And for this I'm trying to mock the Logger and passing to the controller. But it's showing errors:

System.ArgumentNullException : Value cannot be null. (Parameter 'logger')

I tried two approaches but not able to success:

I) Using NullLoggerFactory

private readonly ILogger<TestController> _logger;

        public TestControllerTest()
        {
            _logger = new Logger<TestController>(new NullLoggerFactory());
            _controller = new TestController(_logger);
        }

II) Using Mock.Of

private readonly ILogger<TestController> _logger;

        public TestControllerTest()
        {
            _logger = Mock.Of<ILogger<TestController>>();
            _controller = new TestController(_logger);
        }

c#.netcore logging unit-testing

Views: 13901
Total Answered: 2
Total Marked As Answer: 1
Posted On: 21-Apr-2020 01:34

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Answers

Smith

2890 Points

78 Posts

Try to use following:

private readonly Mock<ILogger<TestController>> _logger;

public TestControllerTest()
{
    _logger = new Mock<ILogger<TestController>>();
    _logger.Setup(m => m.LogError(It.IsAny<Exception>(), It.IsAny<string>()));
    _controller = new TestController(_logger.Object, _service);
    
}

Posted On: 21-Apr-2020 02:56

Thanks Smith. But it's not working to me.

- Priya 21-Apr-2020 04:50

Rahul M...

4916 Points

27 Posts

Please try following:

private readonly Mock<ILogger<TestController>> _logger;

public TestControllerTest()
{
    _logger = new Mock<ILogger<TestResultController>>();
    _controller = new TestController(_logger.Object, _service);
    
}

Posted On: 21-Apr-2020 04:54

Thanks. It works for me.

- Priya 21-Apr-2020 05:00