def test_strftime_date(): assert strftime(date(2015, 1, 2), '%Y-%m-%d') == '2015-01-02'
def test_strftime_datetime(): assert strftime(datetime(2015, 1, 2, 3, 4, 5), '%Y-%m-%d %H:%M:%S') == '2015-01-02 03:04:05'
def test_strftime_none(): assert strftime(None, '%Y-%m-%d') == ''