如何对使用Entity Framework的存储库模式进行单元测试？

Question

我目前正在尝试对通过Entity Framework进行的存储库进行单元测试:

我想要发生的是测试存储库而不实际发送/连接到实际的数据库,我想这样做而不使用任何模拟框架.

目前我的测试是将数据发送到数据库,我想要发生的是测试添加/删除等方法而不将实际数据发送到数据库,因为它仅用于测试.

这是存储库:

namespace AbstractFactory.Repository
{
    using System.Collections.Generic;
    using System.Data.Entity;
    using System.Linq;

    /// <summary>
    /// This class serves as the structure of the Author repository using a database
    /// </summary>
    public class DbAuthorRepository : IRepository<AuthorEntity>
    {

        private AbstractFactoryPatternEntities context;

        public DbAuthorRepository(AbstractFactoryPatternEntities context)
        {
            this.context = context;
        }

        /// <summary>
        /// Adds the specified author.
        /// </summary>
        /// <param name="author">The author.</param>
        public void Add(AuthorEntity author)
        {
            context.AuthorEntities.Add(author);
        }

        /// <summary>
        /// Removes the specified author.
        /// </summary>
        /// <param name="author">The author.</param>
        public void Remove(AuthorEntity author)
        {
            this.context.AuthorEntities.Remove(author);
        }

        /// <summary>
        /// Saves this instance.
        /// </summary>
        public void Save()
        {
            this.context.SaveChanges();
        }

        /// <summary>
        /// Gets all.
        /// </summary>
        /// <returns>returns a list of all the authors</returns>
        public IEnumerable<AuthorEntity> GetAll()
        {
            List<AuthorEntity> result = this.context.AuthorEntities.Include(a => a.Books).ToList();

            return result;
        }

        /// <summary>
        /// Gets the author by id.
        /// </summary>
        /// <param name="id">The id.</param>
        /// <returns>returns an entity</returns>
        public AuthorEntity GetById(int id)
        {
            AuthorEntity result = this.context.AuthorEntities.Single(a => a.AuthorId == id);

            return result;
        }
    }
}

以下是单元测试的当前代码:

[TestMethod]
        public void Add_MethodIsCalled_EntityCountIsIncrementedByOne()
        {
            using (ShimsContext.Create())
            {
                ShimAbstractFactoryPatternEntities context = new ShimAbstractFactoryPatternEntities(new AbstractFactoryPatternEntities());
                DbAuthorRepository repository = new DbAuthorRepository(context);
                repository.Add(new AuthorEntity { FirstName = "Test", LastName = "testing=" });
                var actual = repository.GetAll().Count();
                repository.Save();
                var expected = repository.GetAll().Count();
                Assert.AreNotEqual(actual, expected);
            }

            //AbstractFactoryPatternEntities context = new AbstractFactoryPatternEntities();
            //DbAuthorRepository repository = new DbAuthorRepository(context);
            //var actual = repository.GetAll().Count();
            //repository.Add(new AuthorEntity { FirstName = "Testing", LastName = "MyTest" });
            //repository.Save();
            //var expected = repository.GetAll().Count();
            //Assert.AreNotEqual(actual, expected);
        }

        [TestMethod]
        public void Remove_MethodIsCalled_EntityCountRemainsTheSame()
        {
            AbstractFactoryPatternEntities context = new AbstractFactoryPatternEntities();
            DbAuthorRepository repository = new DbAuthorRepository(context);
            AuthorEntity newAuthor = new AuthorEntity { FirstName = "Testing", LastName = "MyTest" };
            repository.Add(newAuthor);
            repository.Save();
            var actual = repository.GetAll().Count();
            Console.WriteLine(actual);
            repository.Remove(newAuthor);
            var expected = repository.GetAll().Count();
            Console.WriteLine(expected);
            Assert.AreEqual(actual, expected);
        }

        [TestMethod]
        public void Get_MethodIsCalled_CorrectAuthorIsRetrieved()
        {
            AbstractFactoryPatternEntities context = new AbstractFactoryPatternEntities();
            DbAuthorRepository repository = new DbAuthorRepository(context);
            int target = 4;
            AuthorEntity author = repository.GetById(target);
            Assert.AreEqual(target, author.AuthorId);
        }

我想使用shims/stub/fakes来进行测试.

Answer 1

实体框架存储库是存储库接口的具体实现.因为它是具体的,你不能抽象它并在没有数据库的情况下进行测试 - 这个具体实现的重点是将数据写入数据库!

这意味着测试EF存储库的目的应该是验证存储库是否写入实际数据库 - 在测试的行为阶段调用存储库方法,在断言阶段,您可以使用任何其他方式从数据库获取数据(ado.net)或许？)检查存储库是否完成了它的工作.

另一个不相关的事情是,您可以使用存储库的另一个实现,该存储库使用内存数据存储并将此类内存存储库注入其他服务,允许您在不写入物理数据库的情况下测试这些服务.您甚至可以模拟注入其他服务的存储库,只是为了执行一些行为测试,即测试您的服务是否正确使用您的存储库.

Answer 2

您可以使用内存数据库(例如Effort)替换与数据库的连接.然后,您可以测试您的存储库逻辑.更多细节可以在这里找到