Hi Tom,

This is a nice branch. I have a few comments below, and there are some
lint errors.

merge-conditional

-Edwin



== Pyflakes notices ==

lib/lp/bugs/scripts/bugheat.py
    13: 'getUtility' imported but unused
    14: 'implements' imported but unused
    16: 'ITunableLoop' imported but unused
    17: 'DBLoopTuner' imported but unused

lib/lp/bugs/scripts/tests/test_bugheat.py
    10: 'datetime' imported but unused



>=== modified file 'lib/lp/bugs/scripts/bugheat.py'
>--- lib/lp/bugs/scripts/bugheat.py	2010-01-26 20:31:13 +0000
>+++ lib/lp/bugs/scripts/bugheat.py	2010-02-26 21:30:36 +0000
>@@ -8,6 +8,7 @@
>     'BugHeatCalculator',
>     ]
>
>+from datetime import datetime
>
> from zope.component import getUtility
> from zope.interface import implements
>@@ -15,6 +16,8 @@
> from canonical.launchpad.interfaces.looptuner import ITunableLoop
> from canonical.launchpad.utilities.looptuner import DBLoopTuner
>
>+from lp.bugs.interfaces.bugtask import RESOLVED_BUGTASK_STATUSES
>+
>
> class BugHeatConstants:
>
>@@ -63,8 +66,16 @@
>             len(direct_subscribers) + len(subscribers_from_dupes))
>         return subscriber_count * BugHeatConstants.SUBSCRIBER
>
>+    def _bugIsComplete(self):
>+        """Are all the tasks for this bug resolved?"""
>+        return all([(task.status in RESOLVED_BUGTASK_STATUSES)
>+                    for task in self.bug.bugtasks])
>+
>     def getBugHeat(self):
>         """Return the total heat for the current bug."""
>+        if self._bugIsComplete():
>+            return 0
>+
>         total_heat = sum([
>             self._getHeatFromAffectedUsers(),
>             self._getHeatFromDuplicates(),
>@@ -73,5 +84,15 @@
>             self._getHeatFromSubscribers(),
>             ])
>
>+        # Bugs decay over time. Every month the bug isn't touched its heat
>+        # decreeses by 5%.


s/decreeses/decreases/

The comment says 5%, but the test says 10%. Which is it?


>+        months = (
>+            datetime.utcnow() -
>+            self.bug.date_last_updated.replace(tzinfo=None)).days / 30
>+        for i in range(months):
>+            total_heat = total_heat * 0.95



This could be simplified as:
    total_heat *= 0.95 ** months



>+
>+        total_heat = int(total_heat)
>+
>         return total_heat
>
>
>=== modified file 'lib/lp/bugs/scripts/tests/test_bugheat.py'
>--- lib/lp/bugs/scripts/tests/test_bugheat.py	2010-01-12 16:41:23 +0000
>+++ lib/lp/bugs/scripts/tests/test_bugheat.py	2010-02-26 21:30:36 +0000
>@@ -1,4 +1,3 @@
>-
> # Copyright 2010 Canonical Ltd.  This software is licensed under the
> # GNU Affero General Public License version 3 (see the file LICENSE).
>
>@@ -8,12 +7,14 @@
>
> import unittest
>
>+from datetime import datetime, timedelta
>+
> from canonical.testing import LaunchpadZopelessLayer
>
>+from lp.bugs.interfaces.bugtask import BugTaskStatus
> from lp.bugs.scripts.bugheat import BugHeatCalculator, BugHeatConstants
> from lp.testing import TestCaseWithFactory
>
>-
> class TestBugHeatCalculator(TestCaseWithFactory):
>     """Tests for the BugHeatCalculator class."""
>
>@@ -177,6 +178,35 @@
>             "Expected bug heat did not match actual bug heat. "
>             "Expected %s, got %s" % (expected_heat, actual_heat))
>
>+    def test_getBugHeat_complete_bugs(self):
>+        # Bug which are in a resolved status don't have heat at all.
>+        complete_bug = self.factory.makeBug()
>+        heat = BugHeatCalculator(complete_bug).getBugHeat()
>+        self.assertNotEqual(
>+            0, heat,
>+            "Expected bug heat did not match actual bug heat. "
>+            "Expected a positive value, got 0")
>+        complete_bug.bugtasks[0].transitionToStatus(
>+            BugTaskStatus.INVALID, complete_bug.owner)
>+        heat = BugHeatCalculator(complete_bug).getBugHeat()
>+        self.assertEqual(
>+            0, heat,
>+            "Expected bug heat did not match actual bug heat. "
>+            "Expected %s, got %s" % (0, heat))
>+
>+    def test_getBugHeat_decay(self):
>+        # Every month, a bug that wasn't touched has its heat reduced by 10%.



10% or 5% ?



>+        aging_bug = self.factory.makeBug()
>+        aging_bug.date_last_updated = (
>+            aging_bug.date_last_updated - timedelta(days=32))
>+        expected = int((
>+            BugHeatConstants.AFFECTED_USER + BugHeatConstants.SUBSCRIBER) * 0.9)
>+        heat = BugHeatCalculator(aging_bug).getBugHeat()



This test might not notice corner cases. Can you run getBugHeat()
before and after setting the date_last_updated and assert that
old_heat * 0.9 == new_heat



>+        self.assertEqual(
>+            expected, heat,
>+            "Expected bug heat did not match actual bug heat. "
>+            "Expected %s, got %s" % (expected, heat))
>+
>
> def test_suite():
>     return unittest.TestLoader().loadTestsFromName(__name__)
>