fix: compare issue 85 runs across every rerun

Reruns on the upstream merge add commits under the same subjects. The claim needs the base and the patched build present, and one video and audio pair per disc.

tests/test_measurements.py

@@ -538,8 +538,10 @@ class SitePages(unittest.TestCase):
         self.assertLessEqual(set(observations), known, set(observations) - known)
 
     def test_the_issue_85_comparison_holds_in_the_records(self) -> None:
-        """Video and audio equal on each disc across both core commits, card
-        off and on: the sentence the Proof line gives."""
+        """Video and audio equal on each disc across every core commit run,
+        card off and on: the sentence the Proof line gives. The base and the
+        patched build are both there, and reruns on a later upstream base may
+        add commits without changing the claim."""
         said = sm.load_observations(REPO_ROOT / sm.OBSERVATIONS)["issue85-regression-card-on"]["said"]
         self.assertIn("20 discs", said)
         runs: dict[str, list[dict]] = {}
@@ -551,7 +553,8 @@ class SitePages(unittest.TestCase):
         self.assertEqual(len(runs), 20)
         for disc, records in runs.items():
             with self.subTest(disc=disc):
-                self.assertEqual(len({r["core"]["commit"] for r in records}), 2)
+                commits = {r["core"]["commit"][:7] for r in records}
+                self.assertLessEqual({"2ce77e2", "41d7596"}, commits)
                 self.assertEqual({r["subject"] for r in records},
                                  {"issue85-regression-card-off", "issue85-regression-card-on"})
                 seen = {(rep["observables"]["video_sha1"], rep["observables"]["audio_sha1"])