CLN: remove from PeriodIndex.asfreq unnecessary raising ValueError for invalid period freq (#57300)

remove from asfreq unnecessary raising ValueError, correct tests

Author: natmokval

pandas/core/resample.py

@@ -2773,11 +2773,6 @@ def asfreq(
  if isinstance(freq, BaseOffset):
  if hasattr(freq, "_period_dtype_code"):
  freq = freq_to_period_freqstr(freq.n, freq.name)
- else:
- raise ValueError(
- f"Invalid offset: '{freq.base}' for converting time series "
- f"with PeriodIndex."
- )
 
  new_obj = obj.copy()
  new_obj.index = obj.index.asfreq(freq, how=how)

pandas/tests/indexes/period/methods/test_asfreq.py

@@ -142,16 +142,21 @@ def test_asfreq_with_different_n(self):
  tm.assert_series_equal(result, excepted)
 
  @pytest.mark.parametrize(
- "freq",
+ "freq, is_str",
  [
- "2BMS",
- "2YS-MAR",
- "2bh",
+ ("2BMS", True),
+ ("2YS-MAR", True),
+ ("2bh", True),
+ (offsets.MonthBegin(2), False),
+ (offsets.BusinessMonthEnd(2), False),
  ],
  )
- def test_pi_asfreq_not_supported_frequency(self, freq):
- # GH#55785
- msg = f"{freq[1:]} is not supported as period frequency"
+ def test_pi_asfreq_not_supported_frequency(self, freq, is_str):
+ # GH#55785, GH#56945
+ if is_str:
+ msg = f"{freq[1:]} is not supported as period frequency"
+ else:
+ msg = re.escape(f"{freq} is not supported as period frequency")
 
  pi = PeriodIndex(["2020-01-01", "2021-01-01"], freq="M")
  with pytest.raises(ValueError, match=msg):
@@ -172,18 +177,3 @@ def test_pi_asfreq_invalid_frequency(self, freq):
  pi = PeriodIndex(["2020-01-01", "2021-01-01"], freq="M")
  with pytest.raises(ValueError, match=msg):
  pi.asfreq(freq=freq)
-
- @pytest.mark.parametrize(
- "freq",
- [
- offsets.MonthBegin(2),
- offsets.BusinessMonthEnd(2),
- ],
- )
- def test_pi_asfreq_invalid_baseoffset(self, freq):
- # GH#56945
- msg = re.escape(f"{freq} is not supported as period frequency")
-
- pi = PeriodIndex(["2020-01-01", "2021-01-01"], freq="M")
- with pytest.raises(ValueError, match=msg):
- pi.asfreq(freq=freq)

pandas/tests/resample/test_period_index.py

@@ -1,4 +1,5 @@
 from datetime import datetime
+import re
 import warnings
 
 import dateutil
@@ -1034,7 +1035,7 @@ def test_resample_lowercase_frequency_deprecated(
  )
  def test_asfreq_invalid_period_offset(self, offset, frame_or_series):
  # GH#55785
- msg = f"Invalid offset: '{offset.base}' for converting time series "
+ msg = re.escape(f"{offset} is not supported as period frequency")
 
  obj = frame_or_series(range(5), index=period_range("2020-01-01", periods=5))
  with pytest.raises(ValueError, match=msg):