record PyJHora benchmark generation time

tests/test_pyjhora_compare_cli.py

@@ -1,7 +1,10 @@
 import subprocess
 import sys
+from datetime import datetime, timezone
 from pathlib import Path
 
+from benchmarks.jyotish.scripts.run_pyjhora_compare import write_report
+
 
 ROOT = Path(__file__).resolve().parents[1]
 RUNNER = ROOT / "benchmarks" / "jyotish" / "scripts" / "run_pyjhora_compare.py"
@@ -16,3 +19,14 @@ def test_pyjhora_compare_help_is_non_executing():
     assert "--build-local" in result.stdout
     assert "--output-prefix" in result.stdout
     assert "FileNotFoundError" not in result.stderr
+
+
+def test_pyjhora_report_uses_supplied_utc_generation_timestamp():
+    report = write_report(
+        [],
+        [],
+        generated_at=datetime(2026, 7, 15, 4, 30, tzinfo=timezone.utc),
+    )
+
+    assert "生成时间：2026-07-15T04:30:00+00:00" in report
+    assert "生成时间：2026-06-03" not in report