testing entity framework C#

DbTest.cs

 public abstract class DbTest {
    protected MyDbContext Db;
    private DbConnection _connection;
    protected abstract DbConnection DbConnection { get; }

    [SetUp]
    public virtual void Setup() {
        CreateContext(true);
        Db.Database.CreateIfNotExists();
        Db.Database.Initialize(true);
    }

    private void CreateContext(bool isNew) {
        if (_connection == null || isNew) {
            _connection = DbConnection;
        }
        Db = new MyDbContextb(_connection);
    }

    [TearDown]
    public void TearDown() {
        Db.Database.Delete();
        Db.Dispose();
    }

    protected void ExecuteAndSave(Action a) {
        a();
        Db.SaveChanges();
        CreateContext(false);
    }
}

TestProviders.cs

public abstract class InMemoryDbTest : DbTest {
    protected override DbConnection DbConnection {
        //this uses Effort
        get { return DbConnectionFactory.CreateTransient(); }
    }
}

public abstract class LocalDbTest : DbTest {
    protected override DbConnection DbConnection {
        get {
            return new SqlConnection(@"Data Source=(LocalDb)\Projects;Initial Catalog=MyDb.Tests;Integrated Security=true");
        }
    }
}

public abstract class SqlExpress : DbTest {
    protected override DbConnection DbConnection {
        get {
            return new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=MyDb.Tests;Integrated Security=true");
        }
    }
}