Addressing code inspections comments

Author: j-santander

doc/source/whatsnew/v0.19.2.txt

@@ -43,3 +43,4 @@ Bug Fixes
 
 
 - Explicit check in ``to_stata`` and ``StataWriter`` for out-of-range values when writing doubles (:issue:`14618`)
+- Fix AmbiguousTimeError exception when resampling a DatetimeIndex in local TZ, covering a DST change (:issue:`14682`)

pandas/tseries/resample.py

@@ -5,7 +5,6 @@
 
 import pandas as pd
 from pandas.core.base import AbstractMethodError, GroupByMixin
-from pandas.core.config_init import pc_ambiguous_as_wide_doc
 
 from pandas.core.groupby import (BinGrouper, Grouper, _GroupBy, GroupBy,
                                  SeriesGroupBy, groupby, PanelGroupBy)
@@ -1284,6 +1283,10 @@ def _adjust_dates_anchored(first, last, offset, closed='right', base=0):
     #
     # See https://github.com/pandas-dev/pandas/issues/8683
 
+    # 14682 - Since we need to drop the TZ information to perform
+    # the adjustment in the presence of a DST change,
+    # save TZ Info and the DST state of the first and last parameters
+    # so that we can accurately rebuild them at the end.
     first_tzinfo = first.tzinfo
     last_tzinfo = last.tzinfo
     first_dst = bool(first.dst())

pandas/tseries/tests/test_resample.py

@@ -1913,11 +1913,24 @@ def test_resample_size(self):
         assert_series_equal(left, right)
 
     def test_resample_across_dst(self):
-        #14682
+        # The test resamples a DatetimeIndex with values before and after a
+        # DST change
+        # Issue: 14682
+
+        # The DatetimeIndex we will start with
+        # (note that DST happens at 03:00+02:00 -> 02:00+01:00)
+        # 2016-10-30 02:23:00+02:00, 2016-10-30 02:23:00+01:00
         df1 = DataFrame([1477786980, 1477790580], columns=['ts'])
+        dti1 = DatetimeIndex(pd.to_datetime(df1.ts, unit='s')
+                             .dt.tz_localize('UTC')
+                             .dt.tz_convert('Europe/Madrid'))
+
+        # The expected DatetimeIndex after resampling.
+        # 2016-10-30 02:00:00+02:00, 2016-10-30 02:00:00+01:00
         df2 = DataFrame([1477785600, 1477789200], columns=['ts'])
-        dti1 = DatetimeIndex(pd.to_datetime(df1.ts, unit='s').dt.tz_localize('UTC').dt.tz_convert('Europe/Madrid'))
-        dti2 = DatetimeIndex(pd.to_datetime(df2.ts, unit='s').dt.tz_localize('UTC').dt.tz_convert('Europe/Madrid'))
+        dti2 = DatetimeIndex(pd.to_datetime(df2.ts, unit='s')
+                             .dt.tz_localize('UTC')
+                             .dt.tz_convert('Europe/Madrid'))
         df = DataFrame([5, 5], index=dti1)
         assert_frame_equal(
             df.resample(rule='H').sum(),