Dependency injection in Xunit project

Question

I am working on an ASP.Net Core MVC Web application.

My Solution contains 2 projects:

• One for the application and
• A second project, dedicated to unit tests (XUnit).

I have added a reference to the application project in the Tests project.

What I want to do now is to write a class in the XUnit Tests project which will communicate with the database through entity framework.

What I was doing in my application project was to access to my DbContext class through constructor dependency injection.

But I cannot do this in my tests project, because I have no Startup.cs file. In this file I can declare which services will be available.

So what can I do to get a reference to an instance of my DbContext in the test class?

Solution 1

You can implement your own service provider to resolve DbContext.

public class DbFixture
{
    public DbFixture()
    {
        var serviceCollection = new ServiceCollection();
        serviceCollection
            .AddDbContext<SomeContext>(options => options.UseSqlServer("connection string"),
                ServiceLifetime.Transient);

         ServiceProvider = serviceCollection.BuildServiceProvider();
    }

    public ServiceProvider ServiceProvider { get; private set; }
}

public class UnitTest1:IClassFixture<DbFixture>
{
    private ServiceProvider _serviceProvider;

    public UnitTest1(DbFixture fixture)
    {
        _serviceProvider = fixture.ServiceProvider;
    }

    [Fact]
    public void Test1()
    {
        using (var context = _serviceProvider.GetService<SomeContext>())
        {
        }
    }
}

But bear in your mind using EF inside a unit test is not a good idea and it's better to mock DbContext.

The Anatomy of Good Unit Testing

Solution 2

You can use Xunit.DependencyInjection