fix: handle different behavior in rotating table tests at month-end

Two of the tests for update_rotating_tables failed to account for
a different code-path that runs at the end of the month when the
next day is a new month. This change populates the next month
message table entry so that it won't matter if its the end of
the month or not for the tests to run properly.

Closes #502

autopush/tests/test_main.py

@@ -73,12 +73,19 @@ def test_update_rotating_tables(self):
         settings.current_month = last_month.month
         settings.message_tables = {}
 
+        # Create the next month's table, just in case today is the day before
+        # a new month, in which case the lack of keys will cause an error in
+        # update_rotating_tables
+        next_month = get_month(1)
+        settings.message_tables[next_month.month] = None
+
         # Get the deferred back
         e = Deferred()
         d = settings.update_rotating_tables()
 
         def check_tables(result):
-            eq_(len(settings.message_tables), 1)
+            eq_(len(settings.message_tables), 2)
+            eq_(settings.current_month, get_month().month)
 
         d.addCallback(check_tables)
         d.addBoth(lambda x: e.callback(True))
@@ -114,18 +121,25 @@ def check_tables(result):
         return d
 
     def test_update_not_needed(self):
+        from autopush.db import get_month
         settings = AutopushSettings(
             hostname="google.com", resolve_hostname=True)
 
         # Erase the tables it has on init, and move current month back one
         settings.message_tables = {}
 
+        # Create the next month's table, just in case today is the day before
+        # a new month, in which case the lack of keys will cause an error in
+        # update_rotating_tables
+        next_month = get_month(1)
+        settings.message_tables[next_month.month] = None
+
         # Get the deferred back
         e = Deferred()
         d = settings.update_rotating_tables()
 
         def check_tables(result):
-            eq_(len(settings.message_tables), 0)
+            eq_(len(settings.message_tables), 1)
 
         d.addCallback(check_tables)
         d.addBoth(lambda x: e.callback(True))