Added a warning for Scotland calendars

refs #31

Changelog.md

@@ -4,6 +4,8 @@
 
 ### New calendars
 
+**WARNING** Scotland (sub)calendars are highly experimental and because of their very puzzling rules, may be false. Please use them with care.
+
 - Added Scotland calendars, i.e. Scotland, Aberdeen, Angus, Arbroath, Ayr, Carnoustie & Monifieth, Clydebank, Dumfries & Galloway, Dundee, East Dunbartonshire, Edinburgh, Elgin, Falkirk, Fife, Galashiels, Glasgow, Hawick, Inverclyde, Inverness, Kilmarnock, Lochaber, Monifieth, North Lanarkshire, Paisley, Perth, Scottish Borders, South Lanarkshire, Stirling, and West Dunbartonshire (#31).
 
 ### Bugfixes

workalendar/europe/scotland/__init__.py

@@ -23,6 +23,7 @@
 # Since Scotland territories have a lot of different variations, it has become
 # necessary to split this module and associated tests
 from datetime import date, timedelta
+import warnings
 from workalendar.core import WesternCalendar, ChristianMixin
 from workalendar.core import MON, THU, FRI
 from .mixins import (
@@ -64,6 +65,20 @@ class Scotland(WesternCalendar, ChristianMixin):
     include_saint_andrew = False
     include_victoria_day = False
 
+    def __init__(self, *args, **kwargs):
+        super(Scotland, self).__init__(*args, **kwargs)
+        warnings.warn(
+            """
+Please bear in mind that every Scotland (sub)calendar is highly experimental.
+
+It appeared throughout out searches that Scottish calendars have many
+exceptions and somes sources of information contradicts with each other.
+
+As a consequence, we advise our user to treat this Scotland submodule with
+as much care as possible.
+"""
+        )
+
     def get_may_day(self, year):
         """
         May Day is the first Monday in May

workalendar/tests/__init__.py

@@ -9,6 +9,7 @@ class GenericCalendarTest(TestCase):
     cal_class = Calendar
 
     def setUp(self):
-        warnings.simplefilter("ignore")
+        super(GenericCalendarTest, self).setUp()
+        warnings.simplefilter('ignore')
         self.year = date.today().year
         self.cal = self.cal_class()

workalendar/tests/test_scotland.py

@@ -1,5 +1,7 @@
 from datetime import date
-from unittest import TestCase
+from unittest import TestCase, skipIf
+import sys
+import warnings
 
 from workalendar.tests import GenericCalendarTest
 from workalendar.europe import (
@@ -11,6 +13,9 @@
 )
 
 
+PY2 = sys.version_info[0] == 2
+
+
 class GoodFridayTestMixin(object):
     def test_good_friday(self):
         holidays = self.cal.holidays_set(2018)
@@ -270,6 +275,22 @@ class ScotlandTest(GenericCalendarTest):
     """
     cal_class = Scotland
 
+    # For some reason, the Python 2 warnings module doesn't trigger a warning
+    # at each call of constructor ; skipping if we're in a Python2 env.
+    @skipIf(PY2, "Python 2 warnings unsupported")
+    def test_init_warning(self):
+        warnings.simplefilter("always")
+        with warnings.catch_warnings(record=True) as w:
+            # Cause all warnings to always be triggered.
+            # Trigger a warning.
+            self.cal_class()
+            # Verify some things
+            assert len(w) == 1
+            assert issubclass(w[-1].category, UserWarning)
+            assert "experimental" in str(w[-1].message)
+            # Back to normal filtering
+        warnings.simplefilter("ignore")
+
     def test_year_2018(self):
         holidays = self.cal.holidays_set(2018)
         self.assertIn(date(2018, 1, 1), holidays)  # New year's day