public void FirstDayOfWeekInMonthShouldReturnExpectedResult()
{
var date = new DateTime( 2013, 3, 1 );
var expected = new DateTime( 2013, 3, 4 );
var actual = date.FirstDayOfWeekInMonth( DayOfWeek.Monday );
Assert.Equal( expected.Date, actual.Date );
}
public void FirstDayOfWeekInMonthWithCalendarShouldReturnExpectedResult()
{
var date = new DateTime( 2013, 3, 1 );
var calendar = new GregorianFiscalCalendar( 7 );
var expected = new DateTime( 2013, 3, 4 );
var actual = date.FirstDayOfWeekInMonth( DayOfWeek.Monday, calendar );
Assert.Equal( expected.Date, actual.Date );
}
public static DateTime FirstDayOfWeekInMonth( this Calendar calendar, DateTime date, DayOfWeek dayOfWeek )
{
Arg.NotNull( calendar, nameof( calendar ) );
Contract.Ensures( Contract.Result<DateTime>().Month == Contract.OldValue( date.Month ) );
Contract.Ensures( Contract.Result<DateTime>().Year == Contract.OldValue( date.Year ) );
Contract.Ensures( Contract.Result<DateTime>().DayOfWeek == dayOfWeek );
return date.FirstDayOfWeekInMonth( dayOfWeek, calendar );
}