Treat whitespace-only file paths as empty

Co-authored-by: Shri Sukhani <shrisukhani@users.noreply.github.com>

Author: cursoragent

hyperbrowser/client/file_utils.py

@@ -20,7 +20,7 @@ def ensure_existing_file_path(
         ) from exc
     if not isinstance(normalized_path, str):
         raise HyperbrowserError("file_path must resolve to a string path")
-    if not normalized_path:
+    if not normalized_path.strip():
         raise HyperbrowserError("file_path must not be empty")
     if "\x00" in normalized_path:
         raise HyperbrowserError("file_path must not contain null bytes")

tests/test_file_utils.py

@@ -80,6 +80,12 @@ def test_ensure_existing_file_path_rejects_empty_string_paths():
             missing_file_message="missing",
             not_file_message="not-file",
         )
+    with pytest.raises(HyperbrowserError, match="file_path must not be empty"):
+        ensure_existing_file_path(
+            "   ",
+            missing_file_message="missing",
+            not_file_message="not-file",
+        )
 
 
 def test_ensure_existing_file_path_rejects_null_byte_paths():