Mock for Get method not working in mstest

Question

I have a business class called EmployeeService and it is having one method GetProjectsByEmpId and code follows

    public List<Project> GetProjectsByEmpId (int id) {
       return this.empRepository.Get(e=>e.empId == id, e=>e.Projects).Projects;
   }

and Get method synatx is

T Get(Expression<Func<T, bool>> predicate, params Expression<Func<T, object>>[] includes);

and my testcase is

private Mock<IEmployeeRepository> mockEmpRep;
 [TestInitialize]
        public void setup()
        {
            mockEmpRep= new Mock<IEmployeeRepository>();
            myClass= new EmployeeService(mockEmpRep.Object);            
        }

and test method is

 [TestMethod]
    public void Test_GetProjectsByEmpId() {
    this.mockEmpRep.Setup(m=> m.Get(
    It.IsAny<Expression<Func<Employee, bool>>>(),
                    It.IsAny<Expression<Func<Employee, object>>>())).Returns(mockResult);
    var res = myClass.GetProjectsByEmpId(1);
    }

and mockResult is

new Employee { id: 1, projects: List<Project>()}

I am trying to mock for all possible values but I am getting "Parameter count mismatch." error.

Can you please tell me if I am doing anything wrong here. Appreciate your help and thanks in advance.

Answer 1

Here is my full working example. Could you verify and tell me a difference between my solution and your code?

using Microsoft.VisualStudio.TestTools.UnitTesting;
using Moq;
using System;
using System.Collections.Generic;
using System.Linq.Expressions;

namespace UnitTestProject1
{
    public class Project { }

    public class Employee
    {
        public int EmpId { get; set; }
        public List<Project> Projects { get; set; }
    }

    public class EmployeeService
    {
        readonly IEmployeeRepository<Employee> empRepository;

        public EmployeeService(IEmployeeRepository<Employee> repository)
        {
            empRepository = repository;
        }

        public List<Project> GetProjectsByEmpId(int id)
        {
            return empRepository.Get(e => e.EmpId == id, e => e.Projects).Projects;
        }
    }

    public interface IEmployeeRepository<T>
    {
        T Get(Expression<Func<T, bool>> predicate, params Expression<Func<T, object>>[] includes);
    }

    [TestClass]
    public class UnitTest1
    {
        [TestMethod]
        public void TestMethod1()
        {
            var mockEmpRep = new Mock<IEmployeeRepository<Employee>>();
            var mockResult = new Employee() { Projects = new List<Project> { new Project() } };

            mockEmpRep.Setup(
                x => x.Get(
                    It.IsAny<Expression<Func<Employee, bool>>>(),
                    It.IsAny<Expression<Func<Employee, object>>>())
                ).Returns(mockResult);

            EmployeeService myClass = new EmployeeService(mockEmpRep.Object);
            List<Project> result = myClass.GetProjectsByEmpId(1);

            Assert.AreEqual(1, result.Count);
        }
    }
}