public void TestArrageActivitiesAfternoonOnly()
        {
            //Arrange
            var mock = new Mock <IActivitySource>();

            mock.Setup(x => x.GetActivities()).Returns(new List <Activity>
            {
                new Activity("Activity A", new ActivityDuration(TimeUnit.Min, 60)),
                new Activity("Activity B", new ActivityDuration(TimeUnit.Min, 60)),
                new Activity("Activity C", new ActivityDuration(TimeUnit.Min, 45)),
                new Activity("Activity D", new ActivityDuration(TimeUnit.Min, 30)),
            });
            var activitySource    = mock.Object;
            var outputFile        = Path.Combine(Environment.CurrentDirectory, "output.txt");
            var conferenceManager = new ConferenceManager(
                activitySource,
                new TextFileSchedulePrinter(outputFile)
                );

            //Act
            var schedules = new ConferenceSchedule[] {
                new ConferenceSchedule(null, new ConferencePhase(240))
            };

            conferenceManager.Arrange(schedules);
            conferenceManager.Print(schedules);

            //Assert
            Assert.True(schedules.All(x => x.IsValid()));
            Assert.True(schedules[0].Afternoon.Slots.Count == 4);
            Assert.True(File.Exists(outputFile));
        }