fix: judge the gap report on the flat declared set

tests/test_declared_names.py

@@ -0,0 +1,49 @@
+"""The command line report judges "undeclared" on the flat declared set.
+
+Per normalized system id, bk and elektronika-bk never met, nor nintendo-sgb
+and nintendo-super-game-boy: 646 entries whose exact name a platform
+declares were counted undeclared, while verify and the site read one flat
+set, enriched with every spelling the database knows.
+"""
+
+from __future__ import annotations
+
+import sys
+import unittest
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(REPO_ROOT / "scripts"))
+
+from common import load_database, load_emulator_profiles  # noqa: E402
+from cross_reference import (  # noqa: E402
+    _build_supplemental_index,
+    cross_reference,
+    declared_names,
+    load_platform_files,
+)
+
+
+class FlatDeclaredSet(unittest.TestCase):
+    def test_a_name_declared_under_another_system_id_is_not_a_gap(self):
+        if not (REPO_ROOT / "database.json").is_file():
+            self.skipTest("no database.json")
+        db = load_database(str(REPO_ROOT / "database.json"))
+        platforms = str(REPO_ROOT / "platforms")
+        profiles = {k: v for k, v in load_emulator_profiles(str(REPO_ROOT / "emulators")).items() if k == "bk"}
+        if not profiles:
+            self.skipTest("no bk profile")
+        declared, data_dirs = load_platform_files(platforms, ["batocera"])
+        names = _build_supplemental_index()
+        per_system = cross_reference(profiles, declared, db, data_dirs, names)
+        flat = cross_reference(
+            profiles, declared, db, data_dirs, names,
+            all_declared=declared_names(platforms, ["batocera"], db),
+        )
+        gaps = {g["name"] for g in flat["bk"]["gap_details"]}
+        self.assertNotIn("MONIT10.ROM", gaps)
+        self.assertLess(flat["bk"]["gaps"], per_system["bk"]["gaps"])
+
+
+if __name__ == "__main__":
+    unittest.main()