public void GetFirstDayOfWeekReturnsSameDayForFirstDayOfWeek()
        {
            //arrange
            var monday = DateTime.Parse("6 Apr 2015");

            //act
            var actual = PeriodConditionHelper.GetFirstDayOfWeek(monday);

            //assert
            Assert.That(actual, Is.EqualTo(monday));
        }
        public void GetFirstDayOfWeekReturnsMondayDateForDayInMiddleOfWeek()
        {
            //arrange
            var wednesday = DateTime.Parse("8 Apr 2015");

            //act
            var actual = PeriodConditionHelper.GetFirstDayOfWeek(wednesday);

            //assert
            var monday = DateTime.Parse("6 Apr 2015");

            Assert.That(actual, Is.EqualTo(monday));
        }