chore: import upstream snapshot with attribution

tests/scripts/test_update.py

@@ -0,0 +1,124 @@
+from __future__ import annotations
+
+import importlib.util
+from pathlib import Path
+import subprocess
+import sys
+
+
+def _load_update_module():
+    module_path = Path(__file__).resolve().parents[2] / "scripts" / "update.py"
+    module_name = "update_script_under_test"
+    sys.modules.pop(module_name, None)
+    spec = importlib.util.spec_from_file_location(module_name, module_path)
+    assert spec and spec.loader
+    module = importlib.util.module_from_spec(spec)
+    sys.modules[module_name] = module
+    spec.loader.exec_module(module)
+    return module
+
+
+def _run(args: list[str], cwd: Path) -> subprocess.CompletedProcess[str]:
+    return subprocess.run(
+        args,
+        cwd=cwd,
+        check=True,
+        capture_output=True,
+        encoding="utf-8",
+        errors="replace",
+        text=True,
+    )
+
+
+def _git(cwd: Path, *args: str) -> str:
+    return _run(["git", *args], cwd).stdout.strip()
+
+
+def _write(path: Path, text: str) -> None:
+    path.write_text(text, encoding="utf-8")
+
+
+def _commit(repo: Path, message: str) -> None:
+    _git(repo, "add", ".")
+    _git(repo, "commit", "-m", message)
+
+
+def _configure_user(repo: Path) -> None:
+    _git(repo, "config", "user.email", "tests@example.com")
+    _git(repo, "config", "user.name", "DeepTutor Tests")
+
+
+def _create_checkout(tmp_path: Path, branch: str = "main") -> tuple[Path, Path]:
+    remote = tmp_path / "remote.git"
+    seed = tmp_path / "seed"
+    checkout = tmp_path / "checkout"
+
+    _run(["git", "init", "--bare", str(remote)], tmp_path)
+    _run(["git", "init", "-b", branch, str(seed)], tmp_path)
+    _configure_user(seed)
+    _write(seed / "app.txt", "v1\n")
+    _commit(seed, "initial")
+    _git(seed, "remote", "add", "origin", str(remote))
+    _git(seed, "push", "-u", "origin", branch)
+
+    _run(["git", "clone", "--branch", branch, str(remote), str(checkout)], tmp_path)
+    _configure_user(checkout)
+    return seed, checkout
+
+
+def _push_remote_commit(seed: Path, branch: str, text: str = "v2\n") -> None:
+    _write(seed / "app.txt", text)
+    _commit(seed, "remote update")
+    _git(seed, "push", "origin", branch)
+
+
+def test_update_fast_forwards_the_current_non_main_branch(tmp_path: Path) -> None:
+    update = _load_update_module()
+    seed, checkout = _create_checkout(tmp_path, branch="dev")
+    _push_remote_commit(seed, "dev")
+
+    exit_code = update.main(["--repo", str(checkout), "--yes"])
+
+    assert exit_code == 0
+    assert _git(checkout, "branch", "--show-current") == "dev"
+    assert (checkout / "app.txt").read_text(encoding="utf-8") == "v2\n"
+    assert _git(checkout, "rev-parse", "HEAD") == _git(checkout, "rev-parse", "origin/dev")
+
+
+def test_update_refuses_tracked_local_changes(tmp_path: Path) -> None:
+    update = _load_update_module()
+    seed, checkout = _create_checkout(tmp_path)
+    _push_remote_commit(seed, "main")
+    _write(checkout / "app.txt", "local edit\n")
+
+    exit_code = update.main(["--repo", str(checkout), "--yes"])
+
+    assert exit_code == 1
+    assert (checkout / "app.txt").read_text(encoding="utf-8") == "local edit\n"
+    assert _git(checkout, "rev-parse", "HEAD") != _git(checkout, "rev-parse", "origin/main")
+
+
+def test_update_refuses_diverged_branches(tmp_path: Path) -> None:
+    update = _load_update_module()
+    seed, checkout = _create_checkout(tmp_path)
+    _push_remote_commit(seed, "main")
+    _write(checkout / "app.txt", "local commit\n")
+    _commit(checkout, "local update")
+
+    exit_code = update.main(["--repo", str(checkout), "--yes"])
+
+    assert exit_code == 1
+    assert (checkout / "app.txt").read_text(encoding="utf-8") == "local commit\n"
+    assert _git(checkout, "rev-parse", "HEAD") != _git(checkout, "rev-parse", "origin/main")
+
+
+def test_dependency_hints_cover_backend_and_frontend_manifests() -> None:
+    update = _load_update_module()
+
+    hints = update.dependency_hints(
+        ["pyproject.toml", "requirements/server.txt", "web/package-lock.json"]
+    )
+
+    assert len(hints) == 2
+    assert "Backend dependencies changed" in hints[0]
+    assert "Frontend dependencies changed" in hints[1]