chore(repo): retire duplicate nested source mirror

backend/tests/test_repository_layout.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+import importlib.util
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[2]
+SCRIPT = ROOT / "scripts" / "verify_repository_layout.py"
+SPEC = importlib.util.spec_from_file_location("verify_repository_layout", SCRIPT)
+assert SPEC and SPEC.loader
+MODULE = importlib.util.module_from_spec(SPEC)
+SPEC.loader.exec_module(MODULE)
+
+
+def test_nested_repository_mirror_is_absent() -> None:
+    assert MODULE.nested_mirror_markers(ROOT) == []
+
+
+def test_nested_repository_mirror_is_detected(tmp_path: Path) -> None:
+    for marker in MODULE.CANONICAL_MARKERS:
+        path = tmp_path / "geointel" / marker
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_text("fixture", encoding="utf-8")
+
+    assert MODULE.nested_mirror_markers(tmp_path) == list(MODULE.CANONICAL_MARKERS)