refactor(api): apply TG-1107 review feedback

Degrade unmapped disposition values to no_decision instead of raising mid-serialization, matching result_status's tolerant mapping so one odd row never 500s the results page.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: rboni-dk

testgen/api/runs.py

@@ -74,6 +74,20 @@ def get_test_run(job: JobExecution = resolve_job("view", JobExecution.job_key ==
     )
 
 
+def _disposition_from_db(value: str | None) -> Disposition:
+    """Map a stored ``disposition`` to the API enum, degrading unknown values to ``no_decision``.
+
+    A NULL or unmapped value resolves to ``no_decision`` rather than raising, so a single odd
+    row never fails serialization of the whole results page.
+    """
+    if not value:
+        return Disposition.no_decision
+    try:
+        return DISPOSITION_FROM_DB[DbDisposition(value)]
+    except (ValueError, KeyError):
+        return Disposition.no_decision
+
+
 def _to_item(row: TestRunResultRow) -> TestResultItem:
     """Map a DB-valued result row to the API item, normalizing enum casing."""
     return TestResultItem(
@@ -87,7 +101,7 @@ def _to_item(row: TestRunResultRow) -> TestResultItem:
         threshold_value=row.threshold_value,
         result_message=row.message,
         test_time=row.test_time,
-        disposition=DISPOSITION_FROM_DB[DbDisposition(row.disposition)] if row.disposition else Disposition.no_decision,
+        disposition=_disposition_from_db(row.disposition),
     )
 
 

tests/unit/api/test_runs.py

@@ -246,9 +246,11 @@ def test_list_results_status_render(mock_list, db_status, expected):
     "db_disposition,expected",
     [
         (None, Disposition.no_decision),
+        ("", Disposition.no_decision),
         ("Confirmed", Disposition.confirmed),
         ("Dismissed", Disposition.dismissed),
         ("Inactive", Disposition.muted),
+        ("Bogus", Disposition.no_decision),
     ],
 )
 @patch.object(TestResult, "list_for_run")