public void AddStudent(string name, int i)
        {
            var student = new Student()
             {
            Name = name,
            Age = i
             };

             bool isValid = _studentValidator.Validate(student);

             if (isValid)
             {
            _repository.Save(student);
             }
        }
        public void DeleteStudents_should_call_repo_DeleteList_with_matching_Students()
        {
            var student1 = new Student
                              {
                                 Age = 25, Name = "Bob", Id = 1
                              };
             _repository.Stub(d => d.GetStudentById(1))
            .Return(student1);

             var student2 = new Student
                              {
                                 Age = 27, Name = "Mark", Id = 3
                              };
             _repository.Stub(d => d.GetStudentById(3))
            .Return(student2);

             var student3 = new Student
                              {
                                 Age = 35, Name = "Sam", Id = 6
                              };
             _repository.Stub(d => d.GetStudentById(6))
            .Return(student3);

             _studentService.DeleteStudents(new[] {1, 3, 6});
             _repository.AssertWasCalled(d => d.DeleteList(Arg<IEnumerable<Student>>.List.ContainsAll(
            new List<Student>
               {
                  student1,
                  student2,
                  student3,
               })));
        }