content: import pytest
  
  from pandas._libs.tslibs.frequencies import (
      INVALID_FREQ_ERR_MSG,
      _period_str_to_code,
      get_rule_month,
      is_subperiod,
      is_superperiod,
  )
  
  from pandas.tseries import offsets
  
  
  @pytest.mark.parametrize(
      "obj,expected",
      [
          ("W", "DEC"),
          (offsets.Week(), "DEC"),
          ("D", "DEC"),
          (offsets.Day(), "DEC"),
          ("Q", "DEC"),
          (offsets.QuarterEnd(startingMonth=12), "DEC"),
          ("Q-JAN", "JAN"),
          (offsets.QuarterEnd(startingMonth=1), "JAN"),
          ("A-DEC", "DEC"),
          ("Y-DEC", "DEC"),
          (offsets.YearEnd(), "DEC"),
          ("A-MAY", "MAY"),
          ("Y-MAY", "MAY"),
          (offsets.YearEnd(month=5), "MAY"),
      ],
  )
  def test_get_rule_month(obj, expected):
      result = get_rule_month(obj)
      assert result == expected
  
  
  @pytest.mark.parametrize(
      "obj,expected",
      [
          ("A", 1000),
          ("A-DEC", 1000),
          ("A-JAN", 1001),
          ("Y", 1000),
          ("Y-DEC", 1000),
          ("Y-JAN", 1001),
          ("Q", 2000),
          ("Q-DEC", 2000),
          ("Q-FEB", 2002),
          ("W", 4000),
          ("W-SUN", 4000),
          ("W-FRI", 4005),
          ("Min", 8000),
          ("ms", 10000),
          ("US", 11000),
          ("NS", 12000),
      ],
  )
  def test_period_str_to_code(obj, expected):
      assert _period_str_to_code(obj) == expected
  
  
  @pytest.mark.parametrize(
      "p1,p2,expected",
      [
          # Input validation.
          (offsets.MonthEnd(), None, False),
          (offsets.YearEnd(), None, False),
          (None, offsets.YearEnd(), False),
          (None, offsets.MonthEnd(), False),
          (None, None, False),
          (offsets.YearEnd(), offsets.MonthEnd(), True),
          (offsets.Hour(), offsets.Minute(), True),
          (offsets.Second(), offsets.Milli(), True),
          (offsets.Milli(), offsets.Micro(), True),
          (offsets.Micro(), offsets.Nano(), True),
      ],
  )
  def test_super_sub_symmetry(p1, p2, expected):
      assert is_superperiod(p1, p2) is expected
      assert is_subperiod(p2, p1) is expected
  
  
  @pytest.mark.parametrize(
      "freq,expected,aliases",
      [
          ("D", 6000, ["DAY", "DLY", "DAILY"]),
          ("M", 3000, ["MTH", "MONTH", "MONTHLY"]),
          ("N", 12000, ["NANOSECOND", "NANOSECONDLY"]),
          ("H", 7000, ["HR", "HOUR", "HRLY", "HOURLY"]),
          ("T", 8000, ["minute", "MINUTE", "MINUTELY"]),
          ("L", 10000, ["MILLISECOND", "MILLISECONDLY"]),
          ("U", 11000, ["MICROSECOND", "MICROSECONDLY"]),
          ("S", 9000, ["sec", "SEC", "SECOND", "SECONDLY"]),
          ("B", 5000, ["BUS", "BUSINESS", "BUSINESSLY", "WEEKDAY"]),
      ],
  )
  def test_assert_aliases_deprecated(freq, expected, aliases):
      assert isinstance(aliases, list)
      assert _period_str_to_code(freq) == expected
  
      for alias in aliases:
          with pytest.raises(ValueError, match=INVALID_FREQ_ERR_MSG):
              _period_str_to_code(alias)
  