How do I use NSubstitute to mock ILogger on a constructor

Question

I have the following concrete controller constructor:

public class AuthenticationController : ControllerBase
{
    private readonly IUserRepository<User> _userRepository;
    private readonly ILogger<AuthenticationController> _logger;
    private readonly IConfiguration _config;


    public AuthenticationController(IUserRepository<User> userRepository, ILogger<AuthenticationController> logger, IConfiguration config)
    {
        _userRepository = userRepository;
        _logger = logger;
        _config = config;
    }

I'm trying to mock the constructor, but seem to be having trouble with ILogger.

 var userRepository = Substitute.For<IUserRepository<User>>();
 var config = Substitute.For<IConfiguration>();
 var logger = Substitute.For<ILogger>();

 var controller = new AuthenticationController(userRepository, logger, config);

With logger I've tried the following, but all continue to leave a 'red line' under the Constructor : eg. on the line

var controller = new AuthenticationController(userRepository, logger, config);

AuthenticationController has the red line regardless of what I try.

If I declare logger in the form: var logger = Substitute.For<ILogger<AuthenticationController>>(); the whole right side of = also red lines.

var logger = Substitute.For<ILogger<AuthenticationController>>();

then I've tried:

var auth = Substitute.For<AuthenticationController>();
var logger = Substitute.For<ILogger<auth>>();

When I hover over the red line it mentions that the assembly reference on the api is higher than the unit tests assembly. Both projects target .Net Core 2.1

This is the error generating from my test project:

Assembly 'My.Api' with identity 'My.Api, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' uses 'Microsoft.AspNetCore.Mvc.Core, Version=2.1.1.0, Culture=neutral, PublicKeyToken=adb9793829ddae60' which has a higher version than referenced assembly 'Microsoft.AspNetCore.Mvc.Core' with identity 'Microsoft.AspNetCore.Mvc.Core, Version=2.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'

My test project references my api project. The api project has a reference to Microsoft.AspNetCore.App (2.1.1) My unit test project does not have a direct reference at all to this library.

Well, I've never used `Substitute` but in `Moq` framework you pass the object `Mock.Object` or in your scenario - `logger.Object` rather than the mock itself — Fabjan, Jan 10 '19 at 09:01
When you used `For>` what did the error say? That should have worked as far as I can tell. — Mike Zboray, Jan 10 '19 at 09:04
What error do you get (the red line)? From my perspective `Substitute.For>();` should work. — MakePeaceGreatAgain, Jan 10 '19 at 09:07
You may be using the wrong ILogger. Check if your namespaces match. — Connell.O'Donnell, Jan 10 '19 at 09:11
Could you please include the compiler error message in the question? — David Tchepak, Jan 11 '19 at 23:21

score 0 · Answer 1 · answered Jan 10 '19 at 09:35

0

You need to make sure your code project and your unit test project use the same version of the nuget package containing the ILogger.

answered Jan 10 '19 at 09:35

Connell.O'Donnell

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In both projects, If I right mouse click and select 'Go To Definition' both go to the same file `Assembly Microsoft.Extensions.Logging.Abstractions, Version=2.1.1.0, Culture=neutral, PublicKeyToken=adb9793829ddae60` – bilpor Jan 10 '19 at 09:54
That's strange. Have you checked in the NuGet package manager? – Connell.O'Donnell Jan 10 '19 at 09:57

score 0 · Accepted Answer · answered Jan 14 '19 at 11:40

Strange, I created a new test project in the solution and still received the same error. So, in my original test project I installed specifically via Nuget the

Microsoft.AspNetCore.Mvc.Core (2.1.1) package

and my error's went away and it run successfully. I have not specifically referenced this in my Api Project. I've put this up in-case others run into a similar issue.

How do I use NSubstitute to mock ILogger on a constructor

2 Answers2