public void All_ListIsCalled()
        {
            // Arrange

            // Act
            _service.All();

            // Assert
            TeachersRepository.Received().List();
        }
        public void AddTeacher_ValidName_TeacherIsAdded()
        {
            // Arrange

            // Act
            _service.Add("Mohammad Helmy");

            // Assert
            TeachersRepository.Received().Add(Arg.Any <Teacher>());
        }
        protected void _TeacherIdIsEmpty_CreateTeacher(Func <IdNamePair, CourseDetails> act)
        {
            // Arrange
            var name = "Test teacher";

            // Act
            act(new IdNamePair {
                Id = Guid.Empty, Name = name
            });

            // Assert
            TeachersRepository.Received().Add(Arg.Any <Teacher>());
        }