write test for get_clan_flake_toplevel

pkgs/clan-cli/tests/test_dirs.py

@@ -0,0 +1,14 @@
+from pathlib import Path
+
+import pytest
+
+from clan_cli.dirs import get_clan_flake_toplevel
+from clan_cli.errors import ClanError
+
+
+def test_get_clan_flake_toplevel(
+    monkeypatch: pytest.MonkeyPatch, temporary_dir: Path
+) -> None:
+    monkeypatch.chdir(temporary_dir)
+    with pytest.raises(ClanError):
+        get_clan_flake_toplevel()