.NET Core Unit Testing - Mock IOptions

Question

I feel like I\'m missing something really obvious here. I have classes that require injecting of options using the .NET Core IOptions pattern(?). When I unit te

Answer 1

For my system and integration tests I prefer to have a copy/link of my config file inside the test project. And then I use the ConfigurationBuilder to get the options.

using System.Linq;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace SomeProject.Test
{
public static class TestEnvironment
{
    private static object configLock = new object();

    public static ServiceProvider ServiceProvider { get; private set; }
    public static T GetOption()
    {
        lock (configLock)
        {
            if (ServiceProvider != null) return (T)ServiceProvider.GetServices(typeof(T)).First();

            var builder = new ConfigurationBuilder()
                .AddJsonFile("config/appsettings.json", optional: false, reloadOnChange: true)
                .AddEnvironmentVariables();
            var configuration = builder.Build();
            var services = new ServiceCollection();
            services.AddOptions();

            services.Configure(configuration.GetSection("Products"));
            services.Configure(configuration.GetSection("Monitoring"));
            services.Configure(configuration.GetSection("Services"));
            ServiceProvider = services.BuildServiceProvider();
            return (T)ServiceProvider.GetServices(typeof(T)).First();
        }
    }
}
}

This way I can use the config everywhere inside of my TestProject. For unit tests I prefer to use MOQ like patvin80 described.