public interface IAnsweringService
{
    (int code, string desc) GetAnswer(string question);
}


[TestMethod]
public void AnswerToTheUniverseQuestionTest()
{
    var apiMock = Mock.Create<IAnsweringService>();

    var expectedAnswer = new { code = 42, desc = "Answer to the Ultimate Question of Life" };

    Mock.Arrange(() => apiMock.GetAnswer(Arg.AnyString)).Returns(expectedAnswer);

    var actualAnswer = apiMock.GetAnswer("What is a universe question answer?");

    Assert.AreEqual(expectedAnswer.code, actualAnswer.code);
    Assert.AreEqual(expectedAnswer.desc, actualAnswer.desc);
}

Telerik.JustMock.Core.MockException: The chained return value type '<>f__AnonymousType1`2[System.Int32,System.String]' is not compatible with the arranged method's return type 'System.ValueTuple`2[System.Int32,System.String]'