tests: add mock update test

tests/test_update.py

@@ -0,0 +1,35 @@
+from pathlib import Path
+
+import pytest
+
+from depinspect import database
+from depinspect.archives.extract import process_archives
+from depinspect.archives.fetch import fetch_and_save_metadata
+from depinspect.distributions.loader import deserialize_metadata
+
+
+@pytest.fixture
+def data() -> dict[str, dict[str, dict[str, dict[str, str]]]]:
+    return {
+        "ubuntu": {
+            "jammy": {
+                "main": {
+                    "i386": "http://archive.ubuntu.com"
+                    "/ubuntu/dists/jammy/main"
+                    "/binary-i386/Packages.xz"
+                }
+            }
+        }
+    }
+
+
+def test_initialize_from_archives(
+    tmp_path: Path, data: dict[str, dict[str, dict[str, dict[str, str]]]]
+) -> None:
+    fetch_and_save_metadata(data, tmp_path)
+    process_archives(tmp_path)
+    db_path = database.new("ubuntu_test.db", tmp_path)
+    deserialize_metadata(tmp_path, db_path, "ubuntu")
+
+    assert db_path.is_file(), "Database file is not created"
+    assert db_path.suffix == ".db", "Unexpected database file extension"