C#•2y ago

❔ Unit Test | Mocking class with unsafe methods

Hi, I am having trouble writing unit tests, because I dont know how to mock/setup the underlying instance/its methods. The class Silk.NET.OpenCL.CL (https://github.com/dotnet/Silk.NET/blob/main/src/OpenCL/Silk.NET.OpenCL/CL.gen.cs) does not implement an interface and the methods are unsafe and non virtual. This would be one of the methods I need to mock:

public unsafe int GetPlatformIDs(uint num_entries, nint* platforms, out uint num_platforms);

public unsafe int GetPlatformIDs(uint num_entries, nint* platforms, out uint num_platforms);

(instead of out uint num_platforms I could also use uint* num_platforms, if that matters) I tried using Moq, but I run into errors for the null pointer and count parameter:

        unsafe
        {
            var cl = new Mock<CL>();
            cl.Setup(instance => instance.GetPlatformIDs(0, null, out var count)).Returns(0);
            // ....
        }

        unsafe
        {
            var cl = new Mock<CL>();
            cl.Setup(instance => instance.GetPlatformIDs(0, null, out var count)).Returns(0);
            // ....
        }

CS1944: An expression tree may not contain an unsafe pointer operation CS8198: An expression tree may not contain an out argument variable declaration

( I tried also other libraries like Pose, but they all use System.Linq.Expressions.Expression so I always ran into the same errors) Any idea how to do that?

3 Replies

Sergio•2y ago

Use some non-unsafe helper method to do that, and use that one in the test expression?

cap5lutOP•2y ago

I would like to write a test for this method:

    public static IEnumerable<ICLPlatform> GetPlatforms(this CL cl)
    {
        unsafe
        {
            // get the platform count
            var result = cl.GetPlatformIDs(0, null, out var count);
            if (result != (int)ErrorCodes.Success) CLException.Throw(nameof(cl.GetPlatformIDs), result, "Could not get platform IDs");
            if (count == 0) return Enumerable.Empty<CLPlatform>();

            // get all platform IDs
            var platforms = new nint[count];
            fixed (nint* dst = platforms)
            {
                result = cl.GetPlatformIDs(count, dst, null);
                if (result != (int)ErrorCodes.Success) CLException.Throw(nameof(cl.GetPlatformIDs), result, "Could not get platform IDs");
            }

            // map to CLPlatforms
            return platforms.Select(platformId => new CLPlatform(cl, platformId));
        }
    }

    public static IEnumerable<ICLPlatform> GetPlatforms(this CL cl)
    {
        unsafe
        {
            // get the platform count
            var result = cl.GetPlatformIDs(0, null, out var count);
            if (result != (int)ErrorCodes.Success) CLException.Throw(nameof(cl.GetPlatformIDs), result, "Could not get platform IDs");
            if (count == 0) return Enumerable.Empty<CLPlatform>();

            // get all platform IDs
            var platforms = new nint[count];
            fixed (nint* dst = platforms)
            {
                result = cl.GetPlatformIDs(count, dst, null);
                if (result != (int)ErrorCodes.Success) CLException.Throw(nameof(cl.GetPlatformIDs), result, "Could not get platform IDs");
            }

            // map to CLPlatforms
            return platforms.Select(platformId => new CLPlatform(cl, platformId));
        }
    }

guess that would mean i would have to use the mentioned non-unsafe helper method in GetPlatforms() then as well right?

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Unit Test | Mocking class with unsafe methods