BUG: is_normalized returned False for local tz

closes #13459

Author: Ravi Kumar Nimmi <[email protected]>

Closes #13484 from ravinimmi/bugfix and squashes the following commits:

4d48367 [Ravi Kumar Nimmi] BUG: is_normalized returned False for local tz

Author: ravinimmi

doc/source/whatsnew/v0.18.2.txt

@@ -485,6 +485,7 @@ Bug Fixes
 
 - Bug in various index types, which did not propagate the name of passed index (:issue:`12309`)
 - Bug in ``DatetimeIndex``, which did not honour the ``copy=True`` (:issue:`13205`)
+- Bug in ``DatetimeIndex.is_normalized`` returns incorrectly for normalized date_range in case of local timezones (:issue:`13459`)
 
 - Bug in ``DataFrame.to_csv()`` in which float values were being quoted even though quotations were specified for non-numeric values only (:issue:`12922`, :issue:`13259`)
 - Bug in ``MultiIndex`` slicing where extra elements were returned when level is non-unique (:issue:`12896`)

pandas/io/tests/test_pytables.py

@@ -34,7 +34,8 @@
                                  assert_panel_equal,
                                  assert_frame_equal,
                                  assert_series_equal,
-                                 assert_produces_warning)
+                                 assert_produces_warning,
+                                 set_timezone)
 from pandas import concat, Timestamp
 from pandas import compat
 from pandas.compat import range, lrange, u
@@ -5309,14 +5310,6 @@ def test_store_timezone(self):
         # issue storing datetime.date with a timezone as it resets when read
         # back in a new timezone
 
-        import platform
-        if platform.system() == "Windows":
-            raise nose.SkipTest("timezone setting not supported on windows")
-
-        import datetime
-        import time
-        import os
-
         # original method
         with ensure_clean_store(self.path) as store:
 
@@ -5327,34 +5320,17 @@ def test_store_timezone(self):
             assert_frame_equal(result, df)
 
         # with tz setting
-        orig_tz = os.environ.get('TZ')
-
-        def setTZ(tz):
-            if tz is None:
-                try:
-                    del os.environ['TZ']
-                except:
-                    pass
-            else:
-                os.environ['TZ'] = tz
-                time.tzset()
-
-        try:
-
-            with ensure_clean_store(self.path) as store:
+        with ensure_clean_store(self.path) as store:
 
-                setTZ('EST5EDT')
+            with set_timezone('EST5EDT'):
                 today = datetime.date(2013, 9, 10)
                 df = DataFrame([1, 2, 3], index=[today, today, today])
                 store['obj1'] = df
 
-                setTZ('CST6CDT')
+            with set_timezone('CST6CDT'):
                 result = store['obj1']
 
-                assert_frame_equal(result, df)
-
-        finally:
-            setTZ(orig_tz)
+            assert_frame_equal(result, df)
 
     def test_legacy_datetimetz_object(self):
         # legacy from < 0.17.0

pandas/tseries/tests/test_timezones.py

@@ -18,7 +18,7 @@
 
 import pandas.util.testing as tm
 from pandas.types.api import DatetimeTZDtype
-from pandas.util.testing import assert_frame_equal
+from pandas.util.testing import assert_frame_equal, set_timezone
 from pandas.compat import lrange, zip
 
 try:
@@ -1398,6 +1398,26 @@ def test_normalize_tz(self):
         self.assertTrue(result.is_normalized)
         self.assertFalse(rng.is_normalized)
 
+    def test_normalize_tz_local(self):
+        # GH 13459
+        from dateutil.tz import tzlocal
+
+        timezones = ['US/Pacific', 'US/Eastern', 'UTC', 'Asia/Kolkata',
+                     'Asia/Shanghai', 'Australia/Canberra']
+
+        for timezone in timezones:
+            with set_timezone(timezone):
+                rng = date_range('1/1/2000 9:30', periods=10, freq='D',
+                                 tz=tzlocal())
+
+                result = rng.normalize()
+                expected = date_range('1/1/2000', periods=10, freq='D',
+                                      tz=tzlocal())
+                self.assert_index_equal(result, expected)
+
+                self.assertTrue(result.is_normalized)
+                self.assertFalse(rng.is_normalized)
+
     def test_tzaware_offset(self):
         dates = date_range('2012-11-01', periods=3, tz='US/Pacific')
         offset = dates + offsets.Hour(5)

pandas/tslib.pyx

@@ -4810,12 +4810,10 @@ def dates_normalized(ndarray[int64_t] stamps, tz=None):
     elif _is_tzlocal(tz):
         for i in range(n):
             pandas_datetime_to_datetimestruct(stamps[i], PANDAS_FR_ns, &dts)
-            if (dts.min + dts.sec + dts.us) > 0:
-                return False
             dt = datetime(dts.year, dts.month, dts.day, dts.hour, dts.min,
                           dts.sec, dts.us, tz)
             dt = dt + tz.utcoffset(dt)
-            if dt.hour > 0:
+            if (dt.hour + dt.minute + dt.second + dt.microsecond) > 0:
                 return False
     else:
         trans, deltas, typ = _get_dst_info(tz)

pandas/util/testing.py

@@ -2667,3 +2667,50 @@ def patch(ob, attr, value):
             delattr(ob, attr)
         else:
             setattr(ob, attr, old)
+
+
+@contextmanager
+def set_timezone(tz):
+    """Context manager for temporarily setting a timezone.
+
+    Parameters
+    ----------
+    tz : str
+        A string representing a valid timezone.
+
+    Examples
+    --------
+
+    >>> from datetime import datetime
+    >>> from dateutil.tz import tzlocal
+    >>> tzlocal().tzname(datetime.now())
+    'IST'
+
+    >>> with set_timezone('US/Eastern'):
+    ...     tzlocal().tzname(datetime.now())
+    ...
+    'EDT'
+    """
+    if is_platform_windows():
+        import nose
+        raise nose.SkipTest("timezone setting not supported on windows")
+
+    import os
+    import time
+
+    def setTZ(tz):
+        if tz is None:
+            try:
+                del os.environ['TZ']
+            except:
+                pass
+        else:
+            os.environ['TZ'] = tz
+            time.tzset()
+
+    orig_tz = os.environ.get('TZ')
+    setTZ(tz)
+    try:
+        yield
+    finally:
+        setTZ(orig_tz)