added line to whatsnew v0.19.2 and test to test_missing.py in series folder

doc/source/whatsnew/v0.19.2.txt

@@ -38,6 +38,7 @@ Other Enhancements
 Bug Fixes
 ~~~~~~~~~
 
+- Bug in fillna() in which timezone aware datetime64 values were incorrectly rounded (:issue:'14872')
 - Compat with ``dateutil==2.6.0``; segfault reported in the testing suite (:issue:`14621`)
 - Allow ``nanoseconds`` in ``Timestamp.replace`` as a kwarg (:issue:`14621`)
 - Bug in ``pd.read_csv`` in which aliasing was being done for ``na_values`` when passed in as a dictionary (:issue:`14203`)

pandas/tests/series/test_missing.py

@@ -17,6 +17,9 @@ import pandas.util.testing as tm
 
 from .common import TestData
 
+import datetime
+import pytz
+
 
 def _skip_if_no_pchip():
     try:
@@ -908,6 +911,24 @@ class TestSeriesInterpolateData(TestData, tm.TestCase):
                           index=pd.to_timedelta([1, 2, 4]))
         assert_series_equal(result, expected)
 
+    # GH 14872
+    def test_dtype_utc():
+
+        data = pd.Series([pd.NaT, pd.NaT,
+                          datetime.datetime(2016, 12, 12, 22, 24, 6, 100001,
+                                            tzinfo=pytz.utc)])
+
+        filled = data.fillna(method='bfill')
+
+        expected = pd.Series([
+                             datetime.datetime(2016, 12, 12, 22, 24, 6,
+                                               100001, tzinfo=pytz.utc),
+                             datetime.datetime(2016, 12, 12, 22, 24, 6,
+                                               100001, tzinfo=pytz.utc),
+                             datetime.datetime(2016, 12, 12, 22, 24, 6,
+                                               100001, tzinfo=pytz.utc)])
+
+        assert_series_equal(filled, expected)
 
 if __name__ == '__main__':
     import nose

pandas/tests/test_dtype_utc.py

@@ -1,34 +0,0 @@
-#!/usr/bin/env python3
-# -*- coding: utf-8 -*-
-"""
-Created on Sat Dec 17 09:34:47 2016
-
-@author: rodolfoxps
-"""
-import nose
-import pandas as pd
-import datetime
-import pytz
-from pandas.util.testing import assert_series_equal
-
-
-def test_dtype_utc():
-
-    data = pd.Series([pd.NaT, pd.NaT,
-                      datetime.datetime(2016, 12, 12, 22, 24, 6, 100001,
-                                        tzinfo=pytz.utc)])
-
-    filled = data.fillna(method='bfill')
-
-    expected = pd.Series([datetime.datetime(2016, 12, 12, 22, 24, 6, 100001,
-                                            tzinfo=pytz.utc),
-                          datetime.datetime(2016, 12, 12, 22, 24, 6, 100001,
-                                            tzinfo=pytz.utc),
-                          datetime.datetime(2016, 12, 12, 22, 24, 6, 100001,
-                                            tzinfo=pytz.utc)])
-
-    assert_series_equal(filled, expected)
-
-if __name__ == '__main__':
-    nose.runmodule(argv=[__file__, '-vvs', '-x', '--pdb', '--pdb-failure'],
-                   exit=False)