public void PerformanceTestAmountOfGradesGivenById()
        {
            MovieSystem _ms       = new MovieSystem("ratings.json");
            int         movieId   = 1009622;
            int         grade     = 3;
            var         stopwatch = new Stopwatch();

            stopwatch.Start();
            _ms.AmountOfGradesGivenById(movieId, grade);
            stopwatch.Stop();

            var  stop         = stopwatch.ElapsedMilliseconds;
            long expectedTime = 4000;

            Assert.True(stop <= expectedTime);
        }
        public void TestAmountOfGradesGivenById(double expAmount, int movieId, int grade)
        {
            List <Movie> movies = new List <Movie>()
            {
                new Movie {
                    Reviewer = 1, Grade = 1, MovieId = 1
                },
                new Movie {
                    Reviewer = 1, Grade = 1, MovieId = 2
                },
                new Movie {
                    Reviewer = 2, Grade = 2, MovieId = 3
                },
                new Movie {
                    Reviewer = 2, Grade = 2, MovieId = 3
                },
                new Movie {
                    Reviewer = 3, Grade = 4, MovieId = 2
                }
            };
            MovieSystem ms = new MovieSystem(movies);

            Assert.Equal(expAmount, ms.AmountOfGradesGivenById(movieId, grade));
        }