如何进行单元测试。包括用于实体框架的预加载

MyParentEntity entity = null;
using (var dbContext = new MyDbContext(connectionString))
{
    var myRepository = new MyRepository(dbContext);
    entity = myRepository.GetEntityById(1);
} // leave the scope of the DbContext.

// example asserts...
Assert.IsNotNull(entity.Relative, "Relative was not eager loaded."); // Null or EF Exception if proxy attempts to lazy-load.
Assert.IsTrue(entity.Children.Count == 3, "Children were not eager loaded.");