TST: more specific freq attrs

pandas/tests/arrays/categorical/test_constructors.py

@@ -331,6 +331,7 @@ def test_constructor_with_datetimelike(self, dtl):
 
     def test_constructor_from_index_series_datetimetz(self):
         idx = date_range("2015-01-01 10:00", freq="D", periods=3, tz="US/Eastern")
+        idx._set_freq(None)  # freq not preserved in result.categories
         result = Categorical(idx)
         tm.assert_index_equal(result.categories, idx)
 
@@ -339,6 +340,7 @@ def test_constructor_from_index_series_datetimetz(self):
 
     def test_constructor_from_index_series_timedelta(self):
         idx = timedelta_range("1 days", freq="D", periods=3)
+        idx._set_freq(None)  # freq not preserved in result.categories
         result = Categorical(idx)
         tm.assert_index_equal(result.categories, idx)
 

pandas/tests/arrays/test_datetimelike.py

@@ -302,8 +302,14 @@ def test_round(self, tz_naive_fixture):
 
         result = dti.round(freq="2T")
         expected = dti - pd.Timedelta(minutes=1)
+        expected._set_freq(None)
         tm.assert_index_equal(result, expected)
 
+        dta = dti._data
+        result = dta.round(freq="2T")
+        expected = expected._data
+        tm.assert_datetime_array_equal(result, expected)
+
     def test_array_interface(self, datetime_index):
         arr = DatetimeArray(datetime_index)
 

pandas/tests/frame/methods/test_tz_convert.py

@@ -44,6 +44,12 @@ def test_tz_convert_and_localize(self, fn):
             # GH7846
             df2 = DataFrame(np.ones(5), MultiIndex.from_arrays([l0, l1]))
 
+            # freq is not preserved in MultiIndex construction
+            l1_expected._set_freq(None)
+            l0_expected._set_freq(None)
+            l1._set_freq(None)
+            l0._set_freq(None)
+
             df3 = getattr(df2, fn)("US/Pacific", level=0)
             assert not df3.index.levels[0].equals(l0)
             tm.assert_index_equal(df3.index.levels[0], l0_expected)

pandas/tests/frame/test_axis_select_reindex.py

@@ -91,7 +91,8 @@ def test_reindex(self, float_frame):
 
         # pass non-Index
         newFrame = float_frame.reindex(list(datetime_series.index))
-        tm.assert_index_equal(newFrame.index, datetime_series.index)
+        expected = datetime_series.index._with_freq(None)
+        tm.assert_index_equal(newFrame.index, expected)
 
         # copy with no axes
         result = float_frame.reindex()

pandas/tests/frame/test_to_csv.py

@@ -54,6 +54,7 @@ def test_to_csv_from_csv1(self, float_frame, datetime_frame):
             float_frame.to_csv(path, index=False)
 
             # test roundtrip
+            datetime_frame.index._set_freq(None)  # freq does not roundtrip
             datetime_frame.to_csv(path)
             recons = self.read_csv(path)
             tm.assert_frame_equal(datetime_frame, recons)
@@ -1157,6 +1158,7 @@ def test_to_csv_with_dst_transitions(self):
             )
 
             for i in [times, times + pd.Timedelta("10s")]:
+                i._set_freq(None)  # freq is not preserved by read_csv
                 time_range = np.array(range(len(i)), dtype="int64")
                 df = DataFrame({"A": time_range}, index=i)
                 df.to_csv(path, index=True)
@@ -1170,6 +1172,7 @@ def test_to_csv_with_dst_transitions(self):
 
         # GH11619
         idx = pd.date_range("2015-01-01", "2015-12-31", freq="H", tz="Europe/Paris")
+        idx._set_freq(None)  # freq does not round-trip
         df = DataFrame({"values": 1, "idx": idx}, index=idx)
         with tm.ensure_clean("csv_date_format_with_dst") as path:
             df.to_csv(path, index=True)

pandas/tests/groupby/test_timegrouper.py

@@ -8,7 +8,16 @@
 import pytz
 
 import pandas as pd
-from pandas import DataFrame, Index, MultiIndex, Series, Timestamp, date_range
+from pandas import (
+    DataFrame,
+    DatetimeIndex,
+    Index,
+    MultiIndex,
+    Series,
+    Timestamp,
+    date_range,
+    offsets,
+)
 import pandas._testing as tm
 from pandas.core.groupby.grouper import Grouper
 from pandas.core.groupby.ops import BinGrouper
@@ -243,17 +252,20 @@ def test_timegrouper_with_reg_groups(self):
 
             # single groupers
             expected = DataFrame(
-                {"Quantity": [31], "Date": [datetime(2013, 10, 31, 0, 0)]}
-            ).set_index("Date")
+                [[31]],
+                columns=["Quantity"],
+                index=DatetimeIndex(
+                    [datetime(2013, 10, 31, 0, 0)], freq=offsets.MonthEnd(), name="Date"
+                ),
+            )
             result = df.groupby(pd.Grouper(freq="1M")).sum()
             tm.assert_frame_equal(result, expected)
 
             result = df.groupby([pd.Grouper(freq="1M")]).sum()
             tm.assert_frame_equal(result, expected)
 
-            expected = DataFrame(
-                {"Quantity": [31], "Date": [datetime(2013, 11, 30, 0, 0)]}
-            ).set_index("Date")
+            expected.index = expected.index.shift(1)
+            assert expected.index.freq == offsets.MonthEnd()
             result = df.groupby(pd.Grouper(freq="1M", key="Date")).sum()
             tm.assert_frame_equal(result, expected)
 
@@ -448,7 +460,7 @@ def test_groupby_groups_datetimeindex(self):
         for date in dates:
             result = grouped.get_group(date)
             data = [[df.loc[date, "A"], df.loc[date, "B"]]]
-            expected_index = pd.DatetimeIndex([date], name="date")
+            expected_index = pd.DatetimeIndex([date], name="date", freq="D")
             expected = pd.DataFrame(data, columns=list("AB"), index=expected_index)
             tm.assert_frame_equal(result, expected)
 

pandas/tests/indexes/datetimes/test_astype.py

@@ -92,8 +92,10 @@ def test_astype_with_tz(self):
 
         # GH 18951: tz-naive to tz-aware
         idx = date_range("20170101", periods=4)
+        idx._set_freq(None)  # tz_localize does not preserve freq
         result = idx.astype("datetime64[ns, US/Eastern]")
         expected = date_range("20170101", periods=4, tz="US/Eastern")
+        expected._set_freq(None)
         tm.assert_index_equal(result, expected)
 
     def test_astype_str_compat(self):

pandas/tests/indexes/test_base.py

@@ -383,6 +383,7 @@ def test_constructor_dtypes_datetime(self, tz_naive_fixture, attr, klass):
     @pytest.mark.parametrize("klass", [pd.Index, pd.TimedeltaIndex])
     def test_constructor_dtypes_timedelta(self, attr, klass):
         index = pd.timedelta_range("1 days", periods=5)
+        index._set_freq(None)  # wont be preserved by constructors
         dtype = index.dtype
 
         values = getattr(index, attr)

pandas/tests/series/indexing/test_alter_index.py

@@ -75,6 +75,7 @@ def test_reindex_with_datetimes():
 
     result = ts.reindex(list(ts.index[5:10]))
     expected = ts[5:10]
+    expected.index._set_freq(None)
     tm.assert_series_equal(result, expected)
 
     result = ts[list(ts.index[5:10])]
@@ -91,6 +92,7 @@ def test_reindex_corner(datetime_series):
 
     # pass non-Index
     reindexed = datetime_series.reindex(list(datetime_series.index))
+    datetime_series.index._set_freq(None)
     tm.assert_series_equal(datetime_series, reindexed)
 
     # bad fill method

pandas/tests/series/methods/test_sort_index.py

@@ -13,6 +13,8 @@ def test_sort_index_name(self, datetime_series):
         assert result.name == datetime_series.name
 
     def test_sort_index(self, datetime_series):
+        datetime_series.index._set_freq(None)
+
         rindex = list(datetime_series.index)
         random.shuffle(rindex)
 
@@ -45,6 +47,7 @@ def test_sort_index(self, datetime_series):
             random_order.sort_index(level=0, axis=1)
 
     def test_sort_index_inplace(self, datetime_series):
+        datetime_series.index._set_freq(None)
 
         # For GH#11402
         rindex = list(datetime_series.index)

pandas/tests/series/test_datetime_values.py

@@ -233,6 +233,7 @@ def get_dir(s):
         exp_values = pd.date_range(
             "2015-01-01", "2016-01-01", freq="T", tz="UTC"
         ).tz_convert("America/Chicago")
+        exp_values._set_freq(None)  # freq not preserved by tz_localize above
         expected = Series(exp_values, name="xxx")
         tm.assert_series_equal(s, expected)
 

pandas/tests/series/test_io.py

@@ -25,6 +25,7 @@ def read_csv(self, path, **kwargs):
         return out
 
     def test_from_csv(self, datetime_series, string_series):
+        datetime_series.index._set_freq(None)  # freq doesnt round-trip
 
         with tm.ensure_clean() as path:
             datetime_series.to_csv(path, header=False)