public void OutingsRepository_Tests_CalculateIndividualCosts_ShouldBeCorrect()
        {
            Outing sampleOutingOne   = new Outing(EventType.Golf, 20, DateTime.UtcNow, 450m);
            Outing sampleOutingTwo   = new Outing(EventType.Concert, 50, DateTime.UtcNow, 1000m);
            Outing sampleOutingThree = new Outing(EventType.Golf, 4, DateTime.UtcNow, 1000m);

            _outingsRepository.AddToList(sampleOutingOne);
            _outingsRepository.AddToList(sampleOutingTwo);
            _outingsRepository.AddToList(sampleOutingThree);

            decimal actual   = _outingsRepository.CalculateIndividualCosts(EventType.Golf);
            decimal expected = 1450m;

            Assert.AreEqual(expected, actual);
        }