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EntityFramework.Testing

EntityFramework.Testing provides an implementation of IDbAsyncQueryProvider that can be used when testing a component that uses async queries with EntityFramework. You can read more about how to use these components at http://msdn.com/data/dn314429#async.

EntityFramework.Testing.Moq

EntityFramework.Testing.Moq provides some helpful extensions to mock an Entity Framework context and it's DbSets using Moq.

Example

For example, given the following MVC controller.

public class BlogsController : Controller
{
    private readonly BloggingContext db;

    public BlogsController(BloggingContext context)
    {
        db = context;
    }

    public async Task<ViewResult> Index()
    {
        var query = db.Blogs.OrderBy(b => b.Name);

        return View(await query.ToListAsync());
    }
}

You can write a unit test against an mock context as follows. MockDbSet and the SetupSeedData and SetupLinq extension methods are part of EntityFramework.Testing.Moq.

[TestMethod]
public async Task Index_returns_blogs_ordered_by_name()
{
    // Create some test data
    var data = new List<Blog>
    {
        new Blog{ Name = "BBB" },
        new Blog{ Name = "CCC" },
        new Blog{ Name = "AAA" }
    };

    // Create a mock set and context
    var set = new MockDbSet<Blog>()
        .SetupSeedData(data)
        .SetupLinq();

    var context = new Mock<BloggingContext>();
    context.Setup(c => c.Blogs).Returns(set.Object);

    // Create a BlogsController and invoke the Index action
    var controller = new BlogsController(context.Object);
    var result = await controller.Index();

    // Check the results
    var blogs = (List<Blog>)result.Model;
    Assert.AreEqual(3, blogs .Count());
    Assert.AreEqual("AAA", blogs[0].Name);
    Assert.AreEqual("BBB", blogs[1].Name);
    Assert.AreEqual("CCC", blogs[2].Name);
}

APIs

The following APIs can be used on a MockDbSet. You can chain together as many of them as needed to setup the required functionality for each test.

SetupSeedData(data)

SetupSeedData can be used to prepopulate the set with a well-known set of data.

var data = new List<Blog> { new Blog{ Name = "BBB" } };

var set = new MockDbSet<Blog>()
            .SetupSeedData(data);

SetupLinq()

SetupLinq will enable the use of LINQ against the set (and direct enumeration of the set). This includes async LINQ operators.

var set = new MockDbSet<Blog>()
            .SetupLinq();

SetUpAddAndRemove()

SetUpAddAndRemove will enable the DbSet.Add and DbSet.Remove methods to update the local data for the set.

var set = new MockDbSet<Blog>()
            .SetUpAddAndRemove();

SetupFind(finder)

SetupFind allows you to specify a finder function that is used to find entities based on their key values when the DbSet.Find method is called.

var set = new MockDbSet<Blog>()
    .SetupFind((keyValues, blog) => blog.BlogId == (int)keyValues.Single())