test(e2e): add shared binary fixture loader for connector fakes

surfsense_backend/tests/e2e/fakes/binary_loader.py

@@ -0,0 +1,23 @@
+"""Helpers for serving text and binary fixture file bodies."""
+
+from __future__ import annotations
+
+from pathlib import Path
+from typing import Any
+
+
+def _resolve_file_bytes(
+    fixture: dict[str, Any], key: str | None, fixtures_dir: Path
+) -> bytes | None:
+    """Resolve a fake file body, preferring binary fixture files over text."""
+    if not key:
+        return None
+
+    binary_path = fixture.get("_file_binary_paths", {}).get(key)
+    if binary_path is not None:
+        return (fixtures_dir / binary_path).read_bytes()
+
+    content = fixture.get("_file_contents", {}).get(key)
+    if content is None:
+        return None
+    return content.encode("utf-8")