public void GetDifficulties()
        {
            ProjectConfig config = new ProjectConfig();
            IList<TaskDifficulty> difficulties;

            #region StrDifficulties is null

            difficulties = config.GetDifficulties();
            Assert.That(difficulties.Count, Is.EqualTo(5));
            Assert.That(difficulties.Contains(TaskDifficulty.Easiest));
            Assert.That(difficulties.Contains(TaskDifficulty.Easy));
            Assert.That(difficulties.Contains(TaskDifficulty.Common));
            Assert.That(difficulties.Contains(TaskDifficulty.Hard));
            Assert.That(difficulties.Contains(TaskDifficulty.Hardest));

            #endregion

            #region StrDifficulties not null

            config.SetDifficulties(
                new List<TaskDifficulty> 
                {
                    TaskDifficulty.Easy,
                    TaskDifficulty.Hard
                });

            difficulties = config.GetDifficulties();
            Assert.That(difficulties.Count, Is.EqualTo(2));
            Assert.That(difficulties.Contains(TaskDifficulty.Easy));
            Assert.That(difficulties.Contains(TaskDifficulty.Hard));

            #endregion
        }
        public void SetDifficulties()
        {
            ProjectConfig config = new ProjectConfig();

            var difficulties = new List<TaskDifficulty> { TaskDifficulty.Easy, TaskDifficulty.Hard };
            config.SetDifficulties(difficulties);

            var result_difficulties = config.GetDifficulties();
            Assert.That(result_difficulties.Count, Is.EqualTo(2));
            Assert.That(result_difficulties.Contains(TaskDifficulty.Easy));
            Assert.That(result_difficulties.Contains(TaskDifficulty.Hard));
        }