fix: map pc-8801, dsi and cd-i system slugs

tests/test_libretro_slugs.py

@@ -0,0 +1,48 @@
+"""Scraped system ids are slugs the profiles know.
+
+The libretro scraper filed System.dat's PC-8801, DSi and CD-i under
+`nec---pc-8801`, `nintendo---nintendo-dsi` and `philips---cd-i`, fallback
+slugs no profile declares. Target filtering kept the DSi BIOS in packs for
+hardware without a DSi core, and PC-8801 survived only as a hand-added
+duplicate system carrying the quasi88 group.
+"""
+
+from __future__ import annotations
+
+import sys
+import unittest
+from pathlib import Path
+
+import yaml
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(REPO_ROOT / "scripts"))
+
+
+class ScrapedSystemIdsAreSlugs(unittest.TestCase):
+    def test_no_fallback_slug(self):
+        for path in sorted((REPO_ROOT / "platforms").glob("*.yml")):
+            data = yaml.safe_load(path.read_text(encoding="utf-8")) or {}
+            systems = data.get("systems") if isinstance(data, dict) else None
+            for sys_id in systems or {}:
+                with self.subTest(platform=path.stem, system=sys_id):
+                    self.assertNotIn("---", str(sys_id))
+
+    def test_pc88_keeps_the_mk2sr_extension_set(self):
+        """System.dat pairs the mkII SR main ROM with other models' extensions.
+
+        The quasi88 group supplies N88EXT0-3.ROM, which the core reads first
+        (src/LIBRETRO/libretro.c:109-112) and which match that main ROM.
+        """
+        from common import load_platform_config
+
+        config = load_platform_config("retroarch", str(REPO_ROOT / "platforms"))
+        names = {
+            f.get("name") for f in config["systems"]["nec-pc-88"].get("files", [])
+        }
+        for name in ("N88EXT0.ROM", "N88EXT1.ROM", "N88EXT2.ROM", "N88EXT3.ROM"):
+            self.assertIn(name, names)
+
+
+if __name__ == "__main__":
+    unittest.main()