fix: count only shipped files as held by region

tests/test_region_held.py

@@ -0,0 +1,50 @@
+"""A dump the frontend refuses does not hold a regional slot.
+
+platform_region_groups counted a declaration as held as soon as a file
+answered it, hash_mismatch included. On a md5 platform the builder leaves
+that file out as unsafe, so a US file with the wrong md5 displaced a correct
+Japanese one, and the system shipped no BIOS at all.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import os
+import shutil
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(REPO_ROOT / "scripts"))
+
+from packextras import _ships  # noqa: E402
+
+
+class ARefusedDumpHoldsNothing(unittest.TestCase):
+    def test_held_follows_the_frontend(self):
+        (REPO_ROOT / "tmp").mkdir(exist_ok=True)
+        root = Path(tempfile.mkdtemp(dir=REPO_ROOT / "tmp"))
+        self.addCleanup(shutil.rmtree, root, True)
+        previous = os.getcwd()
+        os.chdir(root)
+        self.addCleanup(os.chdir, previous)
+        Path("bios").mkdir()
+        data = b"US BIOS, ANOTHER REVISION"
+        Path("bios/us.bin").write_bytes(data)
+        sha1 = hashlib.sha1(data).hexdigest()
+        db = {
+            "files": {sha1: {"path": "bios/us.bin", "name": "us.bin", "size": len(data),
+                             "md5": hashlib.md5(data).hexdigest(), "crc32": ""}},
+            "indexes": {"by_md5": {}, "by_name": {"us.bin": [sha1]}, "by_crc32": {},
+                        "by_path_suffix": {}},
+        }
+        entry = {"name": "us.bin", "md5": "0" * 32}
+        self.assertFalse(_ships({"verification_mode": "md5"}, entry, db, "us.bin"))
+        self.assertTrue(_ships({"verification_mode": "existence"}, entry, db, "us.bin"))
+        self.assertTrue(_ships({"verification_mode": "md5"}, {"name": "us.bin"}, db, "us.bin"))
+
+
+if __name__ == "__main__":
+    unittest.main()