public void Can_Provide_A_Current_Reporting_Period( int currentYear, int currentMonth, int currentDay, string expectedPeriodShortForm) { var mockDateTimeService = new Mock <IDateTimeService>(); mockDateTimeService .Setup( m => m.UtcNow) .Returns( DateTime .SpecifyKind( new DateTime(currentYear, currentMonth, currentDay), DateTimeKind.Utc)); var SUT = new PeriodService(mockDateTimeService.Object); SUT .GetCurrentPeriod() .PeriodString .Should() .Be(expectedPeriodShortForm); }