Adjust resample expecteds

Author: jbrockmendel

pandas/core/resample.py

@@ -2631,7 +2631,7 @@ def _get_timestamp_range_edges(
     -------
     A tuple of length 2, containing the adjusted pd.Timestamp objects.
     """
-    if isinstance(freq, (Tick, Day)):
+    if isinstance(freq, Tick):
         index_tz = first.tz
         if isinstance(origin, Timestamp) and (origin.tz is None) != (index_tz is None):
             raise ValueError("The origin must have the same timezone as the index.")
@@ -2640,27 +2640,15 @@ def _get_timestamp_range_edges(
             # resampling on the same kind of indexes on different timezones
             origin = Timestamp("1970-01-01", tz=index_tz)
 
-        if isinstance(freq, Day):
-            # _adjust_dates_anchored assumes 'D' means 24h, but first/last
-            # might contain a DST transition (23h, 24h, or 25h).
-            # So "pretend" the dates are naive when adjusting the endpoints
-            first = first.tz_localize(None)
-            last = last.tz_localize(None)
-            if isinstance(origin, Timestamp):
-                origin = origin.tz_localize(None)
-
         first, last = _adjust_dates_anchored(
             first,
             last,
-            cast("Day | Tick", freq),
+            freq,
             closed=closed,
             origin=origin,
             offset=offset,
             unit=unit,
         )
-        if isinstance(freq, Day):
-            first = first.tz_localize(index_tz)
-            last = last.tz_localize(index_tz, nonexistent="shift_forward")
     else:
         first = first.normalize()
         last = last.normalize()
@@ -2752,7 +2740,7 @@ def _insert_nat_bin(
 def _adjust_dates_anchored(
     first: Timestamp,
     last: Timestamp,
-    freq: Tick | Day,
+    freq: Tick,
     closed: Literal["right", "left"] = "right",
     origin: TimeGrouperOrigin = "start_day",
     offset: Timedelta | None = None,
@@ -2768,10 +2756,7 @@ def _adjust_dates_anchored(
     if offset is not None:
         offset = offset.as_unit(unit)
 
-    if isinstance(freq, Day):
-        freq_value = Timedelta(days=freq.n).as_unit(unit)._value
-    else:
-        freq_value = Timedelta(freq).as_unit(unit)._value
+    freq_value = Timedelta(freq).as_unit(unit)._value
 
     origin_timestamp = 0  # origin == "epoch"
     if origin == "start_day":

pandas/tests/resample/test_datetime_index.py

@@ -935,8 +935,9 @@ def _create_series(values, timestamps, freq="D"):
     rng = date_range(start, end, freq="1h").as_unit(unit)
     ts = Series(np.ones(len(rng)), index=rng)
 
-    expected_ts = ["2013-11-02 22:00-05:00", "2013-11-03 22:00-06:00"]
-    expected = _create_series([23.0, 2.0], expected_ts)
+    # GH#61985 changed this to behave like "B" rather than "24h"
+    expected_ts = ["2013-11-03 00:00-05:00"]
+    expected = _create_series([25.0], expected_ts)
     result = ts.resample("D", origin="start", offset="-2h").sum()
     tm.assert_series_equal(result, expected)
 
@@ -945,18 +946,19 @@ def _create_series(values, timestamps, freq="D"):
     result = ts.resample("24h", origin="start", offset="-2h").sum()
     tm.assert_series_equal(result, expected)
 
-    expected_ts = ["2013-11-02 02:00-05:00", "2013-11-03 02:00-06:00"]
-    expected = _create_series([3.0, 22.0], expected_ts)
+    # GH#61985 changed this to behave like "B" rather than "24h"
+    expected_ts = ["2013-11-03 00:00-05:00"]
+    expected = _create_series([25.0], expected_ts)
     result = ts.resample("D", origin="start", offset="2h").sum()
     tm.assert_series_equal(result, expected)
 
-    expected_ts = ["2013-11-02 23:00-05:00", "2013-11-03 23:00-06:00"]
-    expected = _create_series([24.0, 1.0], expected_ts)
+    expected_ts = ["2013-11-03 00:00-05:00"]
+    expected = _create_series([25.0], expected_ts)
     result = ts.resample("D", origin="start", offset="-1h").sum()
     tm.assert_series_equal(result, expected)
 
-    expected_ts = ["2013-11-02 01:00-05:00", "2013-11-03 01:00:00-0500"]
-    expected = _create_series([1.0, 24.0], expected_ts)
+    expected_ts = ["2013-11-03 00:00-05:00"]
+    expected = _create_series([25.0], expected_ts)
     result = ts.resample("D", origin="start", offset="1h").sum()
     tm.assert_series_equal(result, expected)
 

pandas/tests/resample/test_period_index.py

@@ -560,9 +560,10 @@ def test_resample_tz_localized2(self):
         )
         s = Series([1, 2], index=idx)
 
+        # GH#61985 changed this to behave like "B" rather than "24h"
         result = s.resample("D", closed="right", label="right").mean()
-        ex_index = date_range("2001-09-21", periods=1, freq="D", tz="Australia/Sydney")
-        expected = Series([1.5], index=ex_index)
+        ex_index = date_range("2001-09-20", periods=2, freq="D", tz="Australia/Sydney")
+        expected = Series([np.nan, 1.5], index=ex_index)
 
         tm.assert_series_equal(result, expected)