Add protected kit publication and independent version retrieval

Assistant: codex
Assistant-Model: gpt-6.1-sol
Assistant-Session: 01a17f16-d99c-7ea3-95f0-8212897fba6b

tests/test_application_recovery_kit.py

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+import hashlib
+import io
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "scripts"))
+import application_recovery_kit as kit
+
+
+class Missing(Exception):
+    def __init__(self):
+        self.response = {"ResponseMetadata": {"HTTPStatusCode": 404}}
+
+
+class Provider:
+    def __init__(self):
+        self.data, self.calls = None, []
+        self.version = "synthetic-kit-version"
+        self.corrupt = False
+
+    def head_object(self, **args):
+        self.calls.append("head")
+        if self.data is None:
+            raise Missing()
+        return {"ContentLength": len(self.data), "VersionId": self.version,
+                "Metadata": {"sha256": hashlib.sha256(self.data).hexdigest()}}
+
+    def put_object(self, **args):
+        self.calls.append("put")
+        assert args["Bucket"] == kit.BUCKET and args["IfNoneMatch"] == "*"
+        self.data = args["Body"].read()
+        return {"VersionId": self.version}
+
+    def get_object(self, **args):
+        self.calls.append("get")
+        assert args["Bucket"] == kit.BUCKET and args["VersionId"] == self.version
+        body = b"X" * len(self.data) if self.corrupt else self.data
+        return {"VersionId": self.version, "ContentLength": len(body), "Body": io.BytesIO(body)}
+
+
+@pytest.fixture
+def fixture(tmp_path, monkeypatch):
+    tmp_path.chmod(0o700)
+    # Real outside-Git enforcement is covered in identity tests; isolate the
+    # synthetic provider paths from a workstation's possible /tmp Git ancestor.
+    monkeypatch.setattr(kit, "private_directory", kit.archive.private_directory)
+    source = tmp_path / "kit.tar"
+    source.write_bytes(b"synthetic-public-kit-no-private-keys")
+    source.chmod(0o600)
+    return source, Provider()
+
+
+def test_immutable_versioned_kit_readback_and_idempotent_publication(fixture, tmp_path):
+    source, client = fixture
+    ref = kit.publish(client, source)
+    assert ref["automatic_expiry"] is False
+    assert ref["object_key"] == "kits/" + hashlib.sha256(source.read_bytes()).hexdigest() + "/recovery-kit.tar"
+    assert kit.download(client, ref, tmp_path / "fetched.tar")["independently_retrieved_hash_verified"]
+    assert kit.publish(client, source) == ref
+    assert client.calls.count("put") == 1
+
+
+def test_corruption_is_not_accepted_as_independent_kit(fixture, tmp_path):
+    source, client = fixture
+    ref = kit.publish(client, source)
+    client.corrupt = True
+    with pytest.raises(kit.Refused, match="kit_readback_hash_differs"):
+        kit.download(client, ref, tmp_path / "fetched.tar")
+
+
+@pytest.mark.parametrize("field,value", [("project_id", "foreign"), ("bucket", "foreign"),
+                                        ("object_key", "kits/foreign.tar")])
+def test_foreign_reference_refused_before_get(fixture, tmp_path, field, value):
+    source, client = fixture
+    ref = kit.publish(client, source)
+    ref[field] = value
+    with pytest.raises(kit.Refused):
+        kit.download(client, ref, tmp_path / "fetched.tar")
+    assert "get" not in client.calls
+
+
+def test_existing_output_is_never_overwritten(fixture, tmp_path):
+    source, client = fixture
+    ref = kit.publish(client, source)
+    output = tmp_path / "fetched.tar"
+    output.write_bytes(b"keep")
+    with pytest.raises(kit.Refused):
+        kit.download(client, ref, output)
+    assert output.read_bytes() == b"keep"