我如何模拟 FromSql() 方法？

我想知道除了构建一个包装器来嘲笑之外还有什么方法吗FromSql？我知道这个方法是静态的，但是因为他们添加了类似的东西AddEntityFrameworkInMemoryDatabase对于实体框架核心，我认为也可能有一个解决方案，我在我的项目中使用 EF Core 1.0.1。

我的最终目标是测试这个方法：

public List<Models.ClosestLocation> Handle(ClosestLocationsQuery message)
{
    return _context.ClosestLocations.FromSql(
        "EXEC GetClosestLocations {0}, {1}, {2}, {3}",
        message.LocationQuery.Latitude,
        message.LocationQuery.Longitude,
        message.LocationQuery.MaxRecordsToReturn ?? 10,
        message.LocationQuery.Distance ?? 10
    ).ToList();
}

我想确保我的查询是使用我传递给它的相同对象进行处理的，基于这个答案在实体框架 6 中我可以这样做：

[Fact]
public void HandleInvokesGetClosestLocationsWithCorrectData()
{
    var message = new ClosestLocationsQuery
    {
        LocationQuery =
            new LocationQuery {Distance = 1, Latitude = 1.165, Longitude = 1.546, MaxRecordsToReturn = 1}
    };

    var dbSetMock = new Mock<DbSet<Models.ClosestLocation>>();

    dbSetMock.Setup(m => m.FromSql(It.IsAny<string>(), message))
        .Returns(It.IsAny<IQueryable<Models.ClosestLocation>>());

    var contextMock = new Mock<AllReadyContext>();

    contextMock.Setup(c => c.Set<Models.ClosestLocation>()).Returns(dbSetMock.Object);

    var sut = new ClosestLocationsQueryHandler(contextMock.Object);
    var results = sut.Handle(message);

    contextMock.Verify(x => x.ClosestLocations.FromSql(It.IsAny<string>(), It.Is<ClosestLocationsQuery>(y =>
        y.LocationQuery.Distance == message.LocationQuery.Distance &&
        y.LocationQuery.Latitude == message.LocationQuery.Latitude &&
        y.LocationQuery.Longitude == message.LocationQuery.Longitude &&
        y.LocationQuery.MaxRecordsToReturn == message.LocationQuery.MaxRecordsToReturn)));
}

但不同于SqlQuery<T>在 EF 6 中，FromSql<T>在 EF Core 中是静态扩展方法，我问这个问题是因为我认为我可能从错误的角度处理这个问题，或者可能有比包装器更好的替代方案，我很感激对此的任何想法。

我也遇到了同样的情况，菲利普给出的答案有帮助，但主要方法是扔System.ArgumentNullException.

From 这个链接，我终于能够编写一些单元测试了......

这是我正在测试的课程：

public class HolidayDataAccess : IHolidayDataAccess
{
    private readonly IHolidayDataContext holDataContext;

    public HolidayDataAccess(IHolidayDataContext holDataContext)
    {
        this.holDataContext = holDataContext;
    }

    public async Task<IEnumerable<HolidayDate>> GetHolidayDates(DateTime startDate, DateTime endDate)
    {
        using (this.holDataContext)
        {
            IList<HolidayDate> dates = await holDataContext.Dates.FromSql($"[dba].[usp_GetHolidayDates] @StartDate = {startDate}, @EndDate = {endDate}").AsNoTracking().ToListAsync();
            return dates;
        }
    }
}

这是测试方法：

[TestMethod]
public async Task GetHolidayDates_Should_Only_Return_The_Dates_Within_Given_Range()
{
    // Arrange.

        SpAsyncEnumerableQueryable<HolidayDate> dates = new SpAsyncEnumerableQueryable<HolidayDate>();
        dates.Add(new HolidayDate() { Date = new DateTime(2018, 05, 01) });
        dates.Add(new HolidayDate() { Date = new DateTime(2018, 07, 01) });
        dates.Add(new HolidayDate() { Date = new DateTime(2018, 04, 01) });
        dates.Add(new HolidayDate() { Date = new DateTime(2019, 03, 01) });
        dates.Add(new HolidayDate() { Date = new DateTime(2019, 02, 15) });


    var options = new DbContextOptionsBuilder<HolidayDataContext>()
        .UseInMemoryDatabase(databaseName: Guid.NewGuid().ToString())
        .Options;

    HolidayDataContext context = new HolidayDataContext(options);

    context.Dates = context.Dates.MockFromSql(dates);

    HolidayDataAccess dataAccess = new HolidayDataAccess(context);

    //Act.
    IEnumerable<HolidayDate> resutlDates = await dataAccess.GetHolidayDates(new DateTime(2018, 01, 01), new DateTime(2018, 05, 31));

    // Assert.

    Assert.AreEqual(resutlDates.Any(d => d.Date != new DateTime(2019, 03, 01)), true);
    Assert.AreEqual(resutlDates.Any(d => d.Date != new DateTime(2019, 02, 15)), true);

    // we do not need to call this becuase we are using a using block for the context...
    //context.Database.EnsureDeleted();
}

To use UseInMemoryDatabase你需要添加Microsoft.EntityFrameworkCore.InMemory包裹来自NuGet辅助类在这里：

public class SpAsyncEnumerableQueryable<T> : IAsyncEnumerable<T>, IQueryable<T>
{
    private readonly IList<T> listOfSpReocrds;

    public Type ElementType => throw new NotImplementedException();

    public IQueryProvider Provider => new Mock<IQueryProvider>().Object;

    Expression IQueryable.Expression => throw new NotImplementedException();

    public SpAsyncEnumerableQueryable()
    {
        this.listOfSpReocrds = new List<T>();
    }        

    public void Add(T spItem) // this is new method added to allow xxx.Add(new T) style of adding sp records...
    {
        this.listOfSpReocrds.Add(spItem);
    }

    public IEnumerator<T> GetEnumerator()
    {
       return this.listOfSpReocrds.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }

    IAsyncEnumerator<T> IAsyncEnumerable<T>.GetEnumerator()
    {
        return listOfSpReocrds.ToAsyncEnumerable().GetEnumerator();
    }
}

...以及包含 FromSql 方法模拟的 Db 扩展类。

public static class DbSetExtensions
{
    public static DbSet<T> MockFromSql<T>(this DbSet<T> dbSet, SpAsyncEnumerableQueryable<T> spItems) where T : class
    {
        var queryProviderMock = new Mock<IQueryProvider>();
        queryProviderMock.Setup(p => p.CreateQuery<T>(It.IsAny<MethodCallExpression>()))
            .Returns<MethodCallExpression>(x => spItems);

        var dbSetMock = new Mock<DbSet<T>>();
        dbSetMock.As<IQueryable<T>>()
            .SetupGet(q => q.Provider)
            .Returns(() => queryProviderMock.Object);

        dbSetMock.As<IQueryable<T>>()
            .Setup(q => q.Expression)
            .Returns(Expression.Constant(dbSetMock.Object));
        return dbSetMock.Object;
    }
}

希望这可以帮助！

Edits：重构 SpAsyncEnumerableQueryable 类以具有 Add 方法。摆脱了需要 T 数组的参数化构造。已实现IQueryProvider Provider => new Mock<IQueryProvider>().Object;支持.AsNoTracking()。异步调用 ToList。