How to unit test with ILogger in ASP.NET Core
Asked 07 September, 2021
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Votes

This is my controller:

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);
    }
}

As you can see I have 2 dependencies, a IDAO and a ILogger

And this is my test class, I use xUnit to test and Moq to create mock and stub, I can mock DAO easy, but with the ILogger I don't know what to do so I just pass null and comment out the call to log in controller when run test. Is there a way to test but still keep the logger somehow ?

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());
    }
}

15 Answer