Add support for Serbia holidays (#258)

.gitignore

@@ -5,4 +5,5 @@ MANIFEST
 .coverage
 *.egg-info
 *.pyc
-.idea
+.idea
+.vscode/

holidays.py

@@ -5282,3 +5282,49 @@ def _populate(self, year):
 
 class NI(Nicaragua):
     pass
+
+
+class Serbia(HolidayBase):
+    # https://en.wikipedia.org/wiki/Public_holidays_in_Serbia
+
+    def __init__(self, **kwargs):
+        self.country = 'RS'
+        HolidayBase.__init__(self, **kwargs)
+
+    def _populate(self, year):
+        # New Year's Day
+        name = "Нова година"
+        self[date(year, JAN, 1)] = name
+        self[date(year, JAN, 2)] = name
+        if self.observed and date(year, JAN, 1).weekday() in WEEKEND:
+            self[date(year, JAN, 3)] = name + " (Observed)"
+        # Orthodox Christmas
+        name = "Божић"
+        self[date(year, JAN, 7)] = name
+        # Statehood day
+        name = "Дан државности Србије"
+        self[date(year, FEB, 15)] = name
+        self[date(year, FEB, 16)] = name
+        if self.observed and date(year, FEB, 15).weekday() in WEEKEND:
+            self[date(year, FEB, 17)] = name + " (Observed)"
+        # International Workers' Day
+        name = "Празник рада"
+        self[date(year, MAY, 1)] = name
+        self[date(year, MAY, 2)] = name
+        if self.observed and date(year, MAY, 1).weekday() in WEEKEND:
+            self[date(year, MAY, 3)] = name + " (Observed)"
+        # Armistice day
+        name = "Дан примирја у Првом светском рату"
+        self[date(year, NOV, 11)] = name
+        if self.observed and date(year, NOV, 11).weekday() == SUN:
+            self[date(year, NOV, 12)] = name + " (Observed)"
+        # Easter
+        self[easter(year, method=EASTER_ORTHODOX)-rd(days=2)] = "Велики петак"
+        self[easter(year, method=EASTER_ORTHODOX)-rd(days=1)] = "Велика субота"
+        self[easter(year, method=EASTER_ORTHODOX)] = "Васкрс"
+        self[easter(year, method=EASTER_ORTHODOX)+rd(days=1)] = \
+            "Други дан Васкрса"
+
+
+class RS(Serbia):
+    pass

tests.py

@@ -5669,5 +5669,53 @@ def test_ni_holidays_2020(self):
         self.assertIn(date(year, 8, 10), mn_holidays)
 
 
+class TestSerbia(unittest.TestCase):
+    def setUp(self):
+        self.holidays = holidays.Serbia(observed=True)
+
+    def test_new_year(self):
+        # If January 1st is in Weekend, test oberved
+        self.assertIn(date(2017, 1, 1), self.holidays)
+        self.assertIn(date(2017, 1, 2), self.holidays)
+        self.assertIn(date(2017, 1, 3), self.holidays)
+        self.holidays.observed = False
+        self.assertNotIn(date(2017, 1, 3), self.holidays)
+
+    def test_statehood_day(self):
+        # If February 15th is in Weekend, test oberved
+        self.assertIn(date(2020, 2, 15), self.holidays)
+        self.assertIn(date(2020, 2, 16), self.holidays)
+        self.assertIn(date(2020, 2, 17), self.holidays)
+        self.holidays.observed = False
+        self.assertNotIn(date(2020, 2, 17), self.holidays)
+
+    def test_labour_day(self):
+        # If May 1st is in Weekend, test oberved
+        self.assertIn(date(2016, 5, 1), self.holidays)
+        self.assertIn(date(2016, 5, 2), self.holidays)
+        self.assertIn(date(2016, 5, 3), self.holidays)
+        self.holidays.observed = False
+        self.assertNotIn(date(2016, 5, 3), self.holidays)
+
+    def test_armistice_day(self):
+        # If November 11th is in Weekend, test oberved
+        self.assertIn(date(2018, 11, 11), self.holidays)
+        self.assertIn(date(2018, 11, 12), self.holidays)
+        self.holidays.observed = False
+        self.assertNotIn(date(2018, 11, 12), self.holidays)
+
+    def test_religious_holidays(self):
+        # Orthodox Christmas
+        self.assertIn(date(2020, 1, 7), self.holidays)
+        self.assertNotIn(date(2020, 1, 8), self.holidays)
+        # Orthodox Easter
+        self.assertNotIn(date(2020, 4, 16), self.holidays)
+        self.assertIn(date(2020, 4, 17), self.holidays)
+        self.assertIn(date(2020, 4, 18), self.holidays)
+        self.assertIn(date(2020, 4, 19), self.holidays)
+        self.assertIn(date(2020, 4, 20), self.holidays)
+        self.assertNotIn(date(2020, 4, 21), self.holidays)
+
+
 if __name__ == "__main__":
     unittest.main()