fix: resolve region holds with builder inputs

_ships and _emulator_ships resolved without the data directories, the
archive index and the slot override the builder uses: 400 platform
declarations and 178 emulator entries read as missing while the pack
held them.

tests/test_region_held.py

@@ -41,9 +41,66 @@ class ARefusedDumpHoldsNothing(unittest.TestCase):
                         "by_path_suffix": {}},
         }
         entry = {"name": "us.bin", "md5": "0" * 32}
-        self.assertFalse(_ships({"verification_mode": "md5"}, entry, db))
-        self.assertTrue(_ships({"verification_mode": "existence"}, entry, db))
-        self.assertTrue(_ships({"verification_mode": "md5"}, {"name": "us.bin"}, db))
+        def ships(config: dict, fe: dict) -> bool:
+            return _ships(config, fe, db, None, None, None)
+
+        self.assertFalse(ships({"verification_mode": "md5"}, entry))
+        self.assertTrue(ships({"verification_mode": "existence"}, entry))
+        self.assertTrue(ships({"verification_mode": "md5"}, {"name": "us.bin"}))
+
+
+class ADataDirectoryCopyIsHeld(unittest.TestCase):
+    """The region pass resolves with the builder's inputs.
+
+    Without the data directories, AmberELEC's config.ini (served from the
+    bluemsx tree) and dolphin-mmjr2's nwc24msg.cfg (served from the Dolphin
+    Sys tree) read as missing while both packs held them.
+    """
+
+    @classmethod
+    def setUpClass(cls):
+        if not (REPO_ROOT / "data" / "bluemsx").is_dir() or not (
+            REPO_ROOT / "data" / "dolphin-sys"
+        ).is_dir():
+            raise unittest.SkipTest("data/ not refreshed")
+        previous = os.getcwd()
+        os.chdir(REPO_ROOT)
+        try:
+            from common import load_data_dir_registry, load_database
+            from common import load_emulator_profiles, load_platform_config
+            cls.db = load_database("database.json")
+            cls.registry = load_data_dir_registry("platforms")
+            cls.profiles = load_emulator_profiles("emulators")
+            cls.amberelec = load_platform_config("amberelec", "platforms")
+        finally:
+            os.chdir(previous)
+
+    def setUp(self):
+        previous = os.getcwd()
+        os.chdir(REPO_ROOT)
+        self.addCleanup(os.chdir, previous)
+
+    def test_platform_declaration_from_a_data_tree(self):
+        entry = next(
+            fe for fe in self.amberelec["systems"]["coleco-colecovision"]["files"]
+            if fe["destination"].endswith("Dina/config.ini")
+        )
+        self.assertTrue(
+            _ships(self.amberelec, entry, self.db, {}, self.registry, None)
+        )
+
+    def test_emulator_entry_from_a_data_tree(self):
+        from packextras import _emulator_ships
+        from validation import _build_validation_index
+
+        profile = self.profiles["dolphin-mmjr2"]
+        entry = next(
+            fe for fe in profile["files"] if fe.get("name") == "nwc24msg.cfg"
+        )
+        index = _build_validation_index({"dolphin-mmjr2": profile})
+        self.assertTrue(_emulator_ships(
+            entry, "dolphin-mmjr2", profile, self.db, index, {}, self.registry,
+        ))
 
 
 if __name__ == "__main__":