Autofac

As said inside this documentation, autofac enables dependency injection inside your code.
Here is an example :

The code :

[TestFixture]
public class ConfigServiceTests : DatabaseEnabledTestsBase
{
    private IConfigService _configService;
    private IRepository<EntityRecord> _repositoryEntityRecord;
    private IRepository<UniverseRecord> _repositoryUniverseRecord;
    private IRepository<SceneRecord> _repositorySceneRecord;
    private SceneRecord sceneRecord;

    public override void Register(ContainerBuilder builder)
    {
        builder.RegisterType<ConfigService>().As<IConfigService>();
        builder.RegisterType<Repository<EntityRecord>>().As<IRepository<EntityRecord>>();
        builder.RegisterType<Repository<UniverseRecord>>().As<IRepository<UniverseRecord>>();
        builder.RegisterType<Repository<SceneRecord>>().As<IRepository<SceneRecord>>();
    }

    public override void Init()
    {
        base.Init();

        _configService = _container.Resolve<IConfigService>();
        _repositoryEntityRecord = _container.Resolve<IRepository<EntityRecord>>();
        _repositoryUniverseRecord = _container.Resolve<IRepository<UniverseRecord>>();
        _repositorySceneRecord = _container.Resolve<IRepository<SceneRecord>>();
    }
}

Register

public override void Register(ContainerBuilder builder)

ContainerBuilder object is the object in which we will add the dependency injections.

For adding a dependency, we do :

builder.RegisterType<ConfigService>().As<IConfigService>();

• Here, ConfigService is declared as the constructor class to use when IConfigService is called inside the code.
• We could add anything instead of ConfigService, it just have to have the same method declaration that IConfigService interface.

Resolve

_configService = _container.Resolve<IConfigService>();

You just have to know to understand the exemple that previously in the code, from inheritance DatabaseEnabledTestsBase for class ConfigServiceTests, there's lines was realized :

protected IContainer _container;

_container = builder.Build();

So, with _configService = _container.Resolve<IConfigService>(); we said that our variable _configService is fill with an instance of IConfigService, which in real, are a ConfigService, as we declared previously inside the code (register).

• So now, we have an IConfigService _configService instanciated, and we can use it into your tests.

To go futher

There is a many other ways to use autofac, with other functionnalities of it. Here is just an example to get start with autofac.
To go futher, you can read the official documentation or look for some more advance tutorials / articles.