Holiday rename; Juneteenth start_date

doc/source/whatsnew/v1.4.0.rst

@@ -214,6 +214,8 @@ Other enhancements
 - :meth:`Timestamp.isoformat`, now handles the ``timespec`` argument from the base :class:``datetime`` class (:issue:`26131`)
 - :meth:`NaT.to_numpy` ``dtype`` argument is now respected, so ``np.timedelta64`` can be returned (:issue:`44460`)
 - New option ``display.max_dir_items`` customizes the number of columns added to :meth:`Dataframe.__dir__` and suggested for tab completion (:issue:`37996`)
+- Added "Juneteenth National Independence Day" to
+  ``USFederalHolidayCalendar``.  See also `Other API changes`_.
 - :meth:`.Rolling.var`, :meth:`.Expanding.var`, :meth:`.Rolling.std`, :meth:`.Expanding.std` now support `Numba <http://numba.pydata.org/>`_ execution with the ``engine`` keyword (:issue:`44461`)
 
 
@@ -402,6 +404,18 @@ Other API changes
 - :meth:`Index.get_indexer_for` no longer accepts keyword arguments (other than 'target'); in the past these would be silently ignored if the index was not unique (:issue:`42310`)
 - Change in the position of the ``min_rows`` argument in :meth:`DataFrame.to_string` due to change in the docstring (:issue:`44304`)
 - Reduction operations for :class:`DataFrame` or :class:`Series` now raising a ``ValueError`` when ``None`` is passed for ``skipna`` (:issue:`44178`)
+- Changed the ``name`` attribute of several holidays in
+  ``USFederalHolidayCalendar`` to match `official federal holiday
+  names <https://www.opm.gov/policy-data-oversight/pay-leave/federal-holidays/>`_
+  specifically:
+
+   - "New Year's Day" gains the possessive apostrophe
+   - "Presidents Day" becomes "Washington's Birthday"
+   - "Martin Luther King Jr. Day" is now "Birthday of Martin Luther King, Jr."
+   - "July 4th" is now "Independence Day"
+   - "Thanksgiving" is now "Thanksgiving Day"
+   - "Christmas" is now "Christmas Day"
+   - Added "Juneteenth National Independence Day"
 -
 
 .. ---------------------------------------------------------------------------

pandas/tests/tseries/holiday/test_calendar.py

@@ -85,7 +85,7 @@ def test_calendar_observance_dates():
 
 def test_rule_from_name():
     us_fed_cal = get_calendar("USFederalHolidayCalendar")
-    assert us_fed_cal.rule_from_name("Thanksgiving") == USThanksgivingDay
+    assert us_fed_cal.rule_from_name("Thanksgiving Day") == USThanksgivingDay
 
 
 def test_calendar_2031():

pandas/tests/tseries/holiday/test_holiday.py

@@ -164,19 +164,23 @@ def test_holiday_dates(holiday, start_date, end_date, expected):
         (EasterMonday, "2015-04-06", "2015-04-06"),
         (EasterMonday, datetime(2015, 7, 1), []),
         (EasterMonday, "2015-04-05", []),
-        ("New Years Day", "2015-01-01", "2015-01-01"),
-        ("New Years Day", "2010-12-31", "2010-12-31"),
-        ("New Years Day", datetime(2015, 7, 1), []),
-        ("New Years Day", "2011-01-01", []),
-        ("July 4th", "2015-07-03", "2015-07-03"),
-        ("July 4th", datetime(2015, 7, 1), []),
-        ("July 4th", "2015-07-04", []),
+        ("New Year's Day", "2015-01-01", "2015-01-01"),
+        ("New Year's Day", "2010-12-31", "2010-12-31"),
+        ("New Year's Day", datetime(2015, 7, 1), []),
+        ("New Year's Day", "2011-01-01", []),
+        ("Independence Day", "2015-07-03", "2015-07-03"),
+        ("Independence Day", datetime(2015, 7, 1), []),
+        ("Independence Day", "2015-07-04", []),
         ("Veterans Day", "2012-11-12", "2012-11-12"),
         ("Veterans Day", datetime(2015, 7, 1), []),
         ("Veterans Day", "2012-11-11", []),
-        ("Christmas", "2011-12-26", "2011-12-26"),
-        ("Christmas", datetime(2015, 7, 1), []),
-        ("Christmas", "2011-12-25", []),
+        ("Christmas Day", "2011-12-26", "2011-12-26"),
+        ("Christmas Day", datetime(2015, 7, 1), []),
+        ("Christmas Day", "2011-12-25", []),
+        ("Juneteenth National Independence Day", "2020-06-19", []),
+        ("Juneteenth National Independence Day", "2021-06-18", "2021-06-18"),
+        ("Juneteenth National Independence Day", "2022-06-19", []),
+        ("Juneteenth National Independence Day", "2022-06-20", "2022-06-20"),
     ],
 )
 def test_holidays_within_dates(holiday, start, expected):

pandas/tseries/holiday.py

@@ -531,17 +531,17 @@ def merge(self, other, inplace=False):
     "Columbus Day", month=10, day=1, offset=DateOffset(weekday=MO(2))
 )
 USThanksgivingDay = Holiday(
-    "Thanksgiving", month=11, day=1, offset=DateOffset(weekday=TH(4))
+    "Thanksgiving Day", month=11, day=1, offset=DateOffset(weekday=TH(4))
 )
 USMartinLutherKingJr = Holiday(
-    "Martin Luther King Jr. Day",
+    "Birthday of Martin Luther King, Jr.",
     start_date=datetime(1986, 1, 1),
     month=1,
     day=1,
     offset=DateOffset(weekday=MO(3)),
 )
 USPresidentsDay = Holiday(
-    "Presidents Day", month=2, day=1, offset=DateOffset(weekday=MO(3))
+    "Washington’s Birthday", month=2, day=1, offset=DateOffset(weekday=MO(3))
 )
 GoodFriday = Holiday("Good Friday", month=1, day=1, offset=[Easter(), Day(-2)])
 
@@ -556,16 +556,23 @@ class USFederalHolidayCalendar(AbstractHolidayCalendar):
     """
 
     rules = [
-        Holiday("New Years Day", month=1, day=1, observance=nearest_workday),
+        Holiday("New Year's Day", month=1, day=1, observance=nearest_workday),
         USMartinLutherKingJr,
         USPresidentsDay,
         USMemorialDay,
-        Holiday("July 4th", month=7, day=4, observance=nearest_workday),
+        Holiday(
+            "Juneteenth National Independence Day",
+            month=6,
+            day=19,
+            start_date="2021-06-18",
+            observance=nearest_workday,
+        ),
+        Holiday("Independence Day", month=7, day=4, observance=nearest_workday),
         USLaborDay,
         USColumbusDay,
         Holiday("Veterans Day", month=11, day=11, observance=nearest_workday),
         USThanksgivingDay,
-        Holiday("Christmas", month=12, day=25, observance=nearest_workday),
+        Holiday("Christmas Day", month=12, day=25, observance=nearest_workday),
     ]