How can I reset an EF7 InMemory provider between unit tests?

Question

I am trying to use the EF7 InMemory provider for unit tests, but the persistent nature of the InMemory database between tests is causing me problems.

The following code d

Answer 1

I use a DbContext fixture like the following

public class DbContextFixture 
    where TDbContext : DbContext
{
    private readonly DbContextOptions _dbContextOptions = 
        new DbContextOptionsBuilder()
            .UseInMemoryDatabase("_", new InMemoryDatabaseRoot())
            .Options;

    public TDbContext CreateDbContext()
    {
        return (TDbContext)(typeof(TDbContext)
            .GetConstructor(new[] { typeof(DbContextOptions) })
            .Invoke(new[] { _dbContextOptions }));
    }
}

you can now simply do

public class MyRepositoryTests : IDisposable {
    private SchoolContext _context;
    private DbContextFixture _dbContextFixture;

    [TestInitialize]
    public void Setup() {
        _dbContextFixture = new DbContextFixture();
        _context = _dbContextFixture.CreateDbContext();
        _context.Students.AddRange(
            new Student { Id = rng.Next(1,10000), Name = "Able" },
            new Student { Id = rng.Next(1,10000), Name = "Bob" }
        );
        _context.SaveChanges();
    }

    [TestCleanup]
    public void Cleanup()
        _context.Dispose();
        _dbContextFixture = null;
    }

    [TestMethod]
    public void TestMethod1()
    {
        Assert.AreEqual(2, _context.Students.ToList().Count());
    }

    [TestMethod]
    public void TestMethod2()
    {
        Assert.AreEqual(2, _context.Students.ToList().Count());
    }
}

This solution is thread-safe. See my blog for details.