模拟 EF 核心 dbcontext 和 dbset

Question

我正在使用 ASP.NET Core 2.2、EF Core 和 MOQ。当我运行测试时，我收到此错误：消息：System.NotSupportedException：非虚拟（在 VB 中可覆盖）成员上的设置无效：x => x.Movies我做错了什么？public class MovieRepositoryTest{    private readonly MovieRepository _sut;    public MovieRepositoryTest()    {        var moviesMock = CreateDbSetMock(GetFakeListOfMovies());        var mockDbContext = new Mock<MovieDbContext>();        mockDbContext.Setup(x => x.Movies).Returns(moviesMock.Object);        _sut = new MovieRepository(mockDbContext.Object);    }    [Fact]    public void GetAll_WhenCalled_ReturnsAllItems()    {        //Act        var items = _sut.GetAll();        //Assert        Assert.Equal(3, items.Count());    }    private IEnumerable<Movie> GetFakeListOfMovies()    {        var movies = new List<Movie>        {            new Movie {Id = 1, Title = "Movie 1", YearOfRelease = 2018, Genre = "Action"},            new Movie {Id = 2, Title = "Movie 2", YearOfRelease = 2018, Genre = "Action"},            new Movie {Id = 3, Title = "Movie 3", YearOfRelease = 2019, Genre = "Action"}        };        return movies;    }    private static Mock<DbSet<T>> CreateDbSetMock<T>(IEnumerable<T> elements) where T : class    {        var elementsAsQueryable = elements.AsQueryable();        var dbSetMock = new Mock<DbSet<T>>();        dbSetMock.As<IQueryable<T>>().Setup(m => m.Provider).Returns(elementsAsQueryable.Provider);        dbSetMock.As<IQueryable<T>>().Setup(m => m.Expression).Returns(elementsAsQueryable.Expression);        dbSetMock.As<IQueryable<T>>().Setup(m => m.ElementType).Returns(elementsAsQueryable.ElementType);        dbSetMock.As<IQueryable<T>>().Setup(m => m.GetEnumerator()).Returns(elementsAsQueryable.GetEnumerator());        return dbSetMock;    }  }这是我的数据库上下文，带有MoviedbSet：public class MovieDbContext: DbContext{    public MovieDbContext(DbContextOptions<MovieDbContext> options) : base(options)    {    }    public DbSet<Movie> Movies { get; set; }}

Answer 1

我看到您DbContext在MovieRepository. 因此，不使用模拟，使用 EF CoreInMemory数据库将是您的绝佳选择。这也将降低复杂性。

编写您的GetAllTest()方法如下：

[Fact]

public void GetAllTest()

{

        var options = new DbContextOptionsBuilder<MovieDbContext>()

            .UseInMemoryDatabase(databaseName: "MovieListDatabase")

            .Options;

        // Insert seed data into the database using one instance of the context

        using (var context = new MovieDbContext(options))

        {

            context.Movies.Add(new Movie {Id = 1, Title = "Movie 1", YearOfRelease = 2018, Genre = "Action"});

            context.Movies.Add(new Movie {Id = 2, Title = "Movie 2", YearOfRelease = 2018, Genre = "Action"});

            context.Movies.Add(new Movie {Id = 3, Title = "Movie 3", YearOfRelease = 2019, Genre = "Action"});

            context.SaveChanges();

        }

        // Use a clean instance of the context to run the test

        using (var context = new MovieDbContext(options))

        {

            MovieRepository movieRepository = new MovieRepository(context);

            List<Movies> movies == movieRepository.GetAll();

            Assert.Equal(3, movies.Count);

        }

}

注意：不要忘记安装Microsoft.EntityFrameworkCore.InMemorynuget包如下：

安装包 Microsoft.EntityFrameworkCore.InMemory

Answer 2

为了节省您的时间，请尝试使用我的 Moq/NSubstitute 扩展 MockQueryable：https ://github.com/romantitov/MockQueryable 支持所有同步/异步操作

//1 - create a List<T> with test items

var users = new List<UserEntity>()

{

 new UserEntity,

 ...

};

//2 - build mock by extension

var mock = users.AsQueryable().BuildMock();

//3 - setup the mock as Queryable for Moq

_userRepository.Setup(x => x.GetQueryable()).Returns(mock.Object);

//3 - setup the mock as Queryable for NSubstitute

_userRepository.GetQueryable().Returns(mock);

也支持 DbSet

//2 - build mock by extension

var mock = users.AsQueryable().BuildMockDbSet();

//3 - setup DbSet for Moq

var userRepository = new TestDbSetRepository(mock.Object);

//3 - setup DbSet for NSubstitute

var userRepository = new TestDbSetRepository(mock);

笔记：

• 从 1.0.4 版本开始支持 AutoMapper

• 从 1.1.0 版本开始支持 DbQuery

• 从 3.0.0 版本开始支持 EF Core 3.0

Answer 3

使用Moq.EntityFrameworkCore包。

这很简单：

var myDbContextMock = new Mock<MyDbContext>();

IList<Entity> entities = new List<Entity>() { new Entity(), new Entity() };

myDbContextMock.Setup(x => x.Entities).ReturnsDbSet(entities);