add function to get the next holiday

docs/source/examples.rst

@@ -214,6 +214,34 @@ To calculate the number or working days between two specified dates:
 
 Here we calculate the number of working days in Q2 2024.
 
+Getting the next/previous holiday
+---------------------------------
+
+You can request the next/previous holiday of your selected calendar.
+The function returns the date and the name of the holiday - exluding today.
+
+.. code-block:: python
+
+   >>> us_holidays = holidays.US(years=2025)
+   >>> us_holidays.get_next_holiday() # get the next holiday after today
+   (datetime.date(2025, 1, 20), 'Martin Luther King Jr. Day')
+   >>> us_holidays.get_next_holiday(previous=True)  # get the previous holiday before today
+   (datetime.date(2025, 1, 1), "New Year's Day")
+   >>> us_holidays.get_next_holiday("2025-02-01")  # get the next holiday after a specific date
+   (datetime.date(2025, 2, 17), "Washington's Birthday")
+   >>> us_holidays.get_next_holiday("2025-02-01", previous=True)  # get the previous holiday before a specific date
+   (datetime.date(2025, 1, 20), 'Martin Luther King Jr. Day')
+
+If no holiday can be found (e.g. because the date would be after the end date /
+before the start date), (None, None) is returned.
+
+.. code-block:: python
+
+   >>> us_holidays.get_next_holiday("2100-12-31")
+   (None, None)
+   >>> us_holidays.get_next_holiday("1777-01-01", previous=True)
+   (None, None)
+
 Date from holiday name
 ----------------------
 

holidays/holiday_base.py

@@ -959,6 +959,32 @@ def get_named(
 
         raise AttributeError(f"Unknown lookup type: {lookup}")
 
+    def get_entries_sorted(self) -> dict[date, str]:
+        return {k: v for k, v in sorted(self.items(), key=lambda item: item[0])}
+
+    def get_next_holiday(
+        self, start: DateLike = None, previous: bool = False
+    ) -> Union[tuple[date, str], tuple[None, None]]:
+        """Return the date and name of the next holiday from provided date
+        (if previous is False) or the previous holiday (if previous is True).
+        If no date is given the search starts from current date"""
+
+        dt = self.__keytransform__(start) if start else datetime.now().date()
+        if not previous:
+            next_date = next((x for x in self.get_entries_sorted() if x > dt), None)
+            if not next_date and dt.year < self.end_year:
+                self._populate(dt.year + 1)
+                next_date = next((x for x in self.get_entries_sorted() if x > dt), None)
+        else:
+            next_date = next((x for x in reversed(self.get_entries_sorted()) if x < dt), None)
+            if not next_date and dt.year > self.start_year:
+                self._populate(dt.year - 1)
+                next_date = next((x for x in reversed(self.get_entries_sorted()) if x < dt), None)
+        if next_date:
+            return next_date, self.get(next_date)
+        else:
+            return None, None
+
     def get_nth_working_day(self, key: DateLike, n: int) -> date:
         """Return n-th working day from provided date (if n is positive)
         or n-th working day before provided date (if n is negative).

tests/test_holiday_base.py

@@ -1189,3 +1189,103 @@ def test_get_working_days_count(self):
         self.assertEqual(self.hb.get_working_days_count("2024-04-29", "2024-05-04"), 3)
         self.assertEqual(self.hb.get_working_days_count("2024-04-29", "2024-05-05"), 3)
         self.assertEqual(self.hb.get_working_days_count("2024-04-29", "2024-05-06"), 4)
+
+
+class TestNextHoliday(unittest.TestCase):
+    def setUp(self):
+        self.this_year = datetime.now().year
+        self.next_year = self.this_year + 1
+        self.previous_year = self.this_year - 1
+        self.hb = CountryStub3(years=self.this_year)
+        self.next_labor_day_year = (
+            self.this_year
+            if datetime.now().date() < self.hb.get_named("Custom May 1st Holiday")[0]
+            else self.next_year
+        )
+        self.previous_labor_day_year = (
+            self.this_year
+            if datetime.now().date() > self.hb.get_named("Custom May 1st Holiday")[0]
+            else self.previous_year
+        )
+
+    def test_get_next_holiday_forward(self):
+        self.assertEqual(
+            self.hb.get_next_holiday(f"{self.this_year}-01-01"),
+            (date(self.this_year, 5, 1), "Custom May 1st Holiday"),
+        )
+        self.assertEqual(
+            self.hb.get_next_holiday(f"{self.this_year}-04-30"),
+            (date(self.this_year, 5, 1), "Custom May 1st Holiday"),
+        )
+        self.assertEqual(
+            self.hb.get_next_holiday(f"{self.this_year}-05-01"),
+            (date(self.this_year, 5, 2), "Custom May 2nd Holiday"),
+        )
+        self.assertEqual(
+            self.hb.get_next_holiday(f"{self.this_year}-05-02"),
+            (date(self.next_year, 5, 1), "Custom May 1st Holiday"),
+        )
+        self.assertEqual(
+            self.hb.get_next_holiday(f"{self.next_year}-01-01"),
+            (date(self.next_year, 5, 1), "Custom May 1st Holiday"),
+        )
+
+        self.assertIn(
+            self.hb.get_next_holiday(),
+            [
+                (date(self.next_labor_day_year, 5, 1), "Custom May 1st Holiday"),
+                (date(self.next_labor_day_year, 5, 2), "Custom May 2nd Holiday"),
+            ],
+        )
+
+    def test_get_next_holiday_reverse(self):
+        self.assertEqual(
+            self.hb.get_next_holiday(f"{self.this_year}-12-31", previous=True),
+            (date(self.this_year, 5, 2), "Custom May 2nd Holiday"),
+        )
+        self.assertEqual(
+            self.hb.get_next_holiday(f"{self.this_year}-05-02", previous=True),
+            (date(self.this_year, 5, 1), "Custom May 1st Holiday"),
+        )
+        self.assertEqual(
+            self.hb.get_next_holiday(f"{self.this_year}-04-30", previous=True),
+            (date(self.previous_year, 5, 2), "Custom May 2nd Holiday"),
+        )
+        self.assertEqual(
+            self.hb.get_next_holiday(f"{self.previous_year}-12-31", previous=True),
+            (date(self.previous_year, 5, 2), "Custom May 2nd Holiday"),
+        )
+
+        self.assertIn(
+            self.hb.get_next_holiday(previous=True),
+            [
+                (date(self.previous_labor_day_year, 5, 2), "Custom May 2nd Holiday"),
+                (date(self.this_year, 5, 1), "Custom May 1st Holiday"),
+            ],
+        )
+
+    def test_get_next_holiday_corner_cases(self):
+        from holidays.countries.ukraine import UA
+
+        ua = UA()
+        # check for date before start of calendar
+        self.assertEqual(ua.get_next_holiday("1991-01-01", previous=True), (None, None))
+
+        # check for date after end of calendar
+        self.assertEqual(ua.get_next_holiday("2022-03-08"), (None, None))
+
+    def test_get_next_holiday_unsorted_calendars(self):
+        from holidays.countries.united_states import US
+
+        us_calendar = US(years=2024)
+
+        self.assertEqual(
+            us_calendar.get_next_holiday(date(2024, 2, 1)),
+            (date(2024, 2, 19), "Washington's Birthday"),
+        )
+
+        # check for date before start of calendar
+        self.assertEqual(
+            us_calendar.get_next_holiday(date(2024, 2, 1), previous=True),
+            (date(2024, 1, 15), "Martin Luther King Jr. Day"),
+        )