public void Test_AddTrainingGroup()
        {
            Training training = trainingRepository.GetTrainingWithName("Trening funkcionalne snage");

            TrainingPeriod trainingPeriod1 = trainingPeriodRepository.GetTrainingPeriodWithId(6);
            TrainingPeriod trainingPeriod2 = trainingPeriodRepository.GetTrainingPeriodWithId(7);

            TrainingGroup trainingGroup = new TrainingGroup("Grupa za testiranje", training,
                                                            new List <TrainingPeriod> {
                trainingPeriod1, trainingPeriod2
            },
                                                            350.00M);

            trainingGroupRepository.AddTrainingGroup(trainingGroup);

            Assert.IsTrue(trainingGroupRepository.GetAllTrainingGroups().Contains(trainingGroup));

            trainingGroupRepository.RemoveTrainingGroupWithName("Grupa za testiranje");
        }