用lambda和Moq对ServiceLayer进行单元测试

我正在尝试使用Moq测试服务层在我的存储库上使用的lambda。

服务:

public class CompanyService : TuneUpLog.ServiceLayer.ICompanyService
{
    private IRepository<Company> _repository;
    private IValidationDictionary _validatonDictionary;
    private Guid _userId;
    public CompanyService(Guid userId,IValidationDictionary validationDictionary, ObjectContext context)
        : this(userId, validationDictionary, new Repository<Company>(context))
    {
    }
    public CompanyService(Guid userId, IValidationDictionary validationDictionary, IRepository<Company> repository)
    {
        _validatonDictionary = validationDictionary;
        _repository = repository;
        if (userId == Guid.Empty)
            throw new SecurityException("UserId is required");
        else
            _userId = userId;
    }
    public IEnumerable<Company> ListCompany()
    {
        return _repository.Find(c => c.Users.Any(u => u.UserId == _userId));
    }
}

测试:

[TestMethod]
    public void ListCompany_1Valid1Invalid_ReturnsValidCompany()
    {
        Mock<IRepository<Company>> fakeCompanyRepository = new Mock<IRepository<Company>>();
        CompanyService companyService = new CompanyService(USER_ID, new ModelStateWrapper(_modelState), fakeCompanyRepository.Object);
        //1 company for this user and 1 that isn't for this user
        List<Company> companies = new List<Company>()
            {
                new Company() { Id = 1, Name = "Test Company", AccountTypeId = 1, Users = { new User() { UserId = USER_ID } } },
                new Company() { Id = 2, Name = "2nd Test Company", AccountTypeId = 1, Users = { new User() { UserId = Guid.Empty } } }
            };
        fakeCompanyRepository.Setup(c => c.Find(It.IsAny<Expression<Func<Company, bool>>>())).Returns(companies.AsQueryable());
        //count should be 1
        Assert.AreEqual(1, companyService.ListCompany().Count());
    }

存储库:

public interface IRepository<T> where T : class, IEntity
{
    void Add(T newEntity);
    void Edit(T entity);
    IQueryable<T> Find(Expression<Func<T, bool>> predicate);
    IQueryable<T> FindAll();
    T FindById(int id);
    void Remove(T entity);
    void Attach(T entity);
}

测试返回两个公司，而不是我期望的第一个公司。我做错了什么?

fakeCompanyRepository.Setup(
  u => u.Find(It.IsAny<Expression<Func<Company, bool>>>()))
  .Returns(
     //Capture the It.IsAny parameter
     (Expression<Func<Company, bool>> expression) => 
     //Apply it to your queryable.
        companies.AsQueryable().Where(expression));