BUG: resample don't work with non-nanosecond reso (#50774)

* find failing test

* another fixup

* test_sample_size still failing

* some more fixups

* wip

* test_sample_size still failing

* some more fixups

* parametrise over unit for more tests

Co-authored-by: MarcoGorelli <>

Author: MarcoGorelli

pandas/core/arrays/datetimes.py

@@ -1031,7 +1031,7 @@ def tz_localize(
 
         if self.tz is not None:
             if tz is None:
-                new_dates = tz_convert_from_utc(self.asi8, self.tz)
+                new_dates = tz_convert_from_utc(self.asi8, self.tz, reso=self._creso)
             else:
                 raise TypeError("Already tz-aware, use tz_convert to convert.")
         else:

pandas/core/resample.py

@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 import copy
-from datetime import timedelta
 from textwrap import dedent
 from typing import (
     TYPE_CHECKING,
@@ -90,7 +89,6 @@
 )
 from pandas.tseries.offsets import (
     Day,
-    Nano,
     Tick,
 )
 
@@ -1715,7 +1713,7 @@ def _get_time_bins(self, ax: DatetimeIndex):
             name=ax.name,
             ambiguous=True,
             nonexistent="shift_forward",
-        )
+        ).as_unit(ax.unit)
 
         ax_values = ax.asi8
         binner, bin_edges = self._adjust_bin_edges(binner, ax_values)
@@ -1751,7 +1749,11 @@ def _adjust_bin_edges(self, binner, ax_values):
             if self.closed == "right":
                 # GH 21459, GH 9119: Adjust the bins relative to the wall time
                 bin_edges = binner.tz_localize(None)
-                bin_edges = bin_edges + timedelta(1) - Nano(1)
+                bin_edges = (
+                    bin_edges
+                    + Timedelta(days=1, unit=bin_edges.unit).as_unit(bin_edges.unit)
+                    - Timedelta(1, unit=bin_edges.unit).as_unit(bin_edges.unit)
+                )
                 bin_edges = bin_edges.tz_localize(binner.tz).asi8
             else:
                 bin_edges = binner.asi8