Remove redundant obsolete_if_unstable

`obsolete_if_unstable` was introduced by #901 to cover one path:
obsoleting a 'pending' update if it reached its negative karma
threshold. At the time, `check_karma_thresholds` only reached
its negative karma check for updates in 'testing' state, it did
not run on updates in 'pending' state.

However, #1556 extended `check_karma_thresholds` to also run on
updates in 'pending' state, which actually rendered
`obsolete_if_unstable` entirely redundant, except in one case -
calling `comment()` with `check_karma` set to `False` - which
was introduced solely to make it possible to test
`obsolete_if_unstable`.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

bodhi-server/bodhi/server/models.py

@@ -3530,28 +3530,12 @@ def update_bugs(self, bug_ids, session):
         session.flush()
         return new
 
-    def obsolete_if_unstable(self, db):
-        """
-        Obsolete the update if it reached the negative karma threshold while pending.
-
-        Args:
-            db (sqlalchemy.orm.session.Session): A database session.
-        """
-        if self.autokarma and self.status is UpdateStatus.pending \
-                and self.request is UpdateRequest.testing\
-                and self.karma <= self.unstable_karma:
-            log.info("%s has reached unstable karma thresholds", self.alias)
-            self.obsolete(db)
-            log.debug("%s has been obsoleted.", self.alias)
-        return
-
     def comment(self, session, text, karma=0, author=None, karma_critpath=0,
-                bug_feedback=None, testcase_feedback=None, check_karma=True,
-                email_notification=True):
+                bug_feedback=None, testcase_feedback=None, email_notification=True):
         """Add a comment to this update.
 
         If the karma reaches the 'stable_karma' value, then request that this update be marked
-        as stable. If it reaches the 'unstable_karma', it is unpushed.
+        as stable. If it reaches the 'unstable_karma' value, then unpush it (obsolete it).
         """
         if not author:
             raise ValueError('You must provide a comment author')
@@ -3606,7 +3590,7 @@ def comment(self, session, text, karma=0, author=None, karma_critpath=0,
 
             log.info("Updated %s karma to %d", self.alias, self.karma)
 
-            if check_karma and author not in config.get('system_users'):
+            if author not in config.get('system_users'):
                 try:
                     self.check_karma_thresholds(session, 'bodhi')
                 except LockedUpdateException:
@@ -3620,9 +3604,6 @@ def comment(self, session, text, karma=0, author=None, karma_critpath=0,
                         'name': 'karma', 'description': str(e),
                     })
 
-            # Obsolete pending update if it reaches unstable karma threshold
-            self.obsolete_if_unstable(session)
-
         session.flush()
 
         for feedback_dict in bug_feedback:

bodhi-server/tests/test_models.py

@@ -3633,16 +3633,6 @@ def test_last_modified_no_dates(self):
             self.obj.last_modified
         assert 'Update has no timestamps set:' in str(exc.value)
 
-    def test_obsolete_if_unstable_unstable(self):
-        """Test obsolete_if_unstable() when all conditions are met for instability."""
-        self.obj.autokarma = True
-        self.obj.status = UpdateStatus.pending
-        self.obj.request = UpdateRequest.testing
-        self.obj.unstable_karma = -1
-        self.obj.comment(self.db, 'foo', -1, 'foo', check_karma=False)
-
-        assert self.obj.status == UpdateStatus.obsolete
-
     @mock.patch('bodhi.server.models.log.warning')
     def test_remove_tag_emptystring(self, warning):
         """Test remove_tag() with a tag of ''."""