fix: install the variant the pack ships

tests/test_validated_choice.py

@@ -0,0 +1,104 @@
+"""The pack and the install manifest place the same bytes at a destination.
+
+The builder replaced a file an emulator rejects by a held variant both
+accept; the manifest kept the first resolution. install.py then placed the
+PS2 ROM2.BIN at galaksija/ROM2.BIN where the pack carried the Galaksija ROM,
+across 14 destinations on six platforms.
+"""
+
+from __future__ import annotations
+
+import ast
+import hashlib
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(REPO_ROOT / "scripts"))
+
+from validation import (  # noqa: E402
+    _build_validation_index,
+    destination_owners,
+    validated_choice,
+)
+
+
+class ValidatedChoice(unittest.TestCase):
+    def test_a_rejected_file_gives_way_to_an_accepted_variant(self):
+        with tempfile.TemporaryDirectory(dir=REPO_ROOT / "tmp") as tmp:
+            wrong = Path(tmp) / "ps2" / "ROM2.BIN"
+            right = Path(tmp) / "galaksija" / "ROM2.BIN"
+            wrong.parent.mkdir()
+            right.parent.mkdir()
+            wrong.write_bytes(b"p" * 64)
+            right.write_bytes(b"g" * 4096)
+            db = {
+                "files": {
+                    hashlib.sha1(p.read_bytes()).hexdigest(): {
+                        "path": str(p),
+                        "name": "ROM2.BIN",
+                        "size": p.stat().st_size,
+                        "md5": hashlib.md5(p.read_bytes()).hexdigest(),
+                    }
+                    for p in (wrong, right)
+                },
+                "indexes": {"by_name": {}, "by_md5": {}},
+            }
+            db["indexes"]["by_name"]["ROM2.BIN"] = list(db["files"])
+            index = _build_validation_index({
+                "galaksija": {
+                    "emulator": "galaksija",
+                    "files": [{"name": "ROM2.BIN", "size": 4096, "validation": ["size"]}],
+                }
+            })
+            chosen, disagreement = validated_choice(
+                {"name": "ROM2.BIN"}, str(wrong), db, index, tmp, None
+            )
+            self.assertEqual(chosen, str(right))
+            self.assertIsNone(disagreement)
+
+    def test_a_destination_another_emulator_owns_is_not_judged(self):
+        """ZEsarUX's 48 KB cpc6128.rom check gave ep128emu the composite image."""
+        profiles = {
+            "zesarux": {"files": [
+                {"name": "cpc6128.rom", "size": 49152, "validation": ["size"]},
+            ]},
+            "ep128emu": {"files": [
+                {"name": "cpc6128.rom", "path": "ep128emu/roms/cpc6128.rom"},
+            ]},
+        }
+        index = _build_validation_index(profiles)
+        owners = destination_owners(profiles)
+        with tempfile.TemporaryDirectory(dir=REPO_ROOT / "tmp") as tmp:
+            rom = Path(tmp) / "cpc6128.rom"
+            rom.write_bytes(b"c" * 32768)
+            db = {"files": {}, "indexes": {"by_name": {}, "by_md5": {}}}
+            for destination, judged in (
+                ("ep128emu/roms/cpc6128.rom", False),
+                ("cpc6128.rom", True),
+            ):
+                with self.subTest(destination=destination):
+                    _chosen, disagreement = validated_choice(
+                        {"name": "cpc6128.rom"}, str(rom), db, index, tmp, None,
+                        destination, owners,
+                    )
+                    self.assertEqual(disagreement is not None, judged)
+
+    def test_pack_and_manifest_both_read_it(self):
+        tree = ast.parse((REPO_ROOT / "scripts" / "generate_pack.py").read_text(encoding="utf-8"))
+        callers = {
+            node.name
+            for node in ast.walk(tree)
+            if isinstance(node, ast.FunctionDef)
+            and any(
+                isinstance(call, ast.Call) and getattr(call.func, "id", None) == "validated_choice"
+                for call in ast.walk(node)
+            )
+        }
+        self.assertLessEqual({"generate_pack", "generate_manifest"}, callers)
+
+
+if __name__ == "__main__":
+    unittest.main()