起订量和DbFunctions [英] Moq and DbFunctions

问题描述

目前，我正在尝试运行在一个通过实体框架运行查询一些单元测试。查询本身运行，而无需在现场版的​​任何问题，但单元测试总是失败。

I'm currently attempting to run some unit tests on a query that is running through the Entity Framework. The query itself runs without any issues on the live version, but the unit tests are always failing.

我已经缩小下来到我的DbFunctions.TruncateTime的用法，但我不知道解决的办法来获得单元测试，以反映什么是活的服务器上发生的情况。

I've narrowed this down to my usage of DbFunctions.TruncateTime, but I don't know of a way around this to get the unit tests to reflect what is happening on the live server.

下面是我使用的方法：

    public System.Data.DataTable GetLinkedUsers(int parentUserId)
    {
        var today = DateTime.Now.Date;

        var query = from up in DB.par_UserPlacement
                    where up.MentorId == mentorUserId
                        && DbFunctions.TruncateTime(today) >= DbFunctions.TruncateTime(up.StartDate)
                        && DbFunctions.TruncateTime(today) <= DbFunctions.TruncateTime(up.EndDate)
                    select new
                    {
                        up.UserPlacementId,
                        up.Users.UserId,
                        up.Users.FirstName,
                        up.Users.LastName,
                        up.Placements.PlacementId,
                        up.Placements.PlacementName,
                        up.StartDate,
                        up.EndDate,
                    };

        query = query.OrderBy(up => up.EndDate);

        return this.RunQueryToDataTable(query);
    }

如果我注释掉在，测试全部通过DbFunctions行（除对于正在检查对于给定的日期唯一有效的结果运行）的那些。

If I comment out the lines with DbFunctions in, the tests all pass (except for the ones that are checking that only valid results for a given date are run).

有我可以提供DbFunctions.TruncateTime的一个模拟版本在这些试验中使用的？ 。本质上，它应该只返回Datetime.Date，但不是在EF查询可用

Is there I can provide a mock version of DbFunctions.TruncateTime to use in these tests? Essentially it should just be returning Datetime.Date, but that isn't available in EF queries.

编辑：下面是失败的，试验使用日期检查：

Here's the test that's failing that uses the date check:

    [TestMethod]
    public void CanOnlyGetCurrentLinkedUsers()
    {
        var up = new List<par_UserPlacement>
        {
            this.UserPlacementFactory(1, 2, 1), // Create a user placement that is current
            this.UserPlacementFactory(1, 3, 2, false) // Create a user placement that is not current
        }.AsQueryable();

        var set = DLTestHelper.GetMockSet<par_UserPlacement>(up);

        var context = DLTestHelper.Context;
        context.Setup(c => c.par_UserPlacement).Returns(set.Object);

        var getter = DLTestHelper.New<LinqUserGetLinkedUsersForParentUser>(context.Object);

        var output = getter.GetLinkedUsers(1);

        var users = new List<User>();
        output.ProcessDataTable((DataRow row) => students.Add(new UserStudent(row)));

        Assert.AreEqual(1, users.Count);
        Assert.AreEqual(2, users[0].UserId);
    }

编辑2：这是消息和调试从相关测试跟踪：

Edit 2: This is the message and debug trace from the test in question:

Test Result: Failed

Message: Assert.AreEqual failed. Expected:<1>. Actual:<0>

Debug Trace: This function can only be invoked from LINQ to Entities

从我读过的东西，这是因为没有一个LINQ到实体实现这个方法，可以在这个地方的单元测试中使用的，虽然有在现场的版本（因为它是一个查询SQL服务器）。

From what I've read, this is because there isn't a LINQ to Entities implementation of this method that could be used in this place for the Unit Test, although there is on the live version (as it's querying an SQL server).

推荐答案

感谢所有帮助大家，我设法追查上垫片看完后为我工作的解决方案qujck提及。添加的EntityFramework的假组装后，我可以将其更改为以下解决这些测试：

Thanks for all of the help everyone, I managed to track down a solution that worked for me after reading up on shims that qujck mentioned. After adding a fake assembly of EntityFramework, I was able to fix these tests by changing them to the following:

[TestMethod]
public void CanOnlyGetCurrentLinkedUsers()
{
    using (ShimsContext.Create())
    {
        System.Data.Entity.Fakes.ShimDbFunctions.TruncateTimeNullableOfDateTime =
            (DateTime? input) =>
            {
                return input.HasValue ? (DateTime?)input.Value.Date : null;
            };

        var up = new List<par_UserPlacement>
        {
            this.UserPlacementFactory(1, 2, 1), // Create a user placement that is current
            this.UserPlacementFactory(1, 3, 2, false) // Create a user placement that is not current
        }.AsQueryable();

        var set = DLTestHelper.GetMockSet<par_UserPlacement>(up);

        var context = DLTestHelper.Context;
        context.Setup(c => c.par_UserPlacement).Returns(set.Object);

        var getter = DLTestHelper.New<LinqUserGetLinkedUsersForParentUser>(context.Object);

        var output = getter.GetLinkedUsers(1);
    }

    var users = new List<User>();
    output.ProcessDataTable((DataRow row) => users.Add(new User(row)));

    Assert.AreEqual(1, users.Count);
    Assert.AreEqual(2, users[0].UserId);
}

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