Validate file utility error message arguments

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

Author: cursoragent

hyperbrowser/client/file_utils.py

@@ -11,6 +11,14 @@ def ensure_existing_file_path(
     missing_file_message: str,
     not_file_message: str,
 ) -> str:
+    if not isinstance(missing_file_message, str):
+        raise HyperbrowserError("missing_file_message must be a string")
+    if not missing_file_message.strip():
+        raise HyperbrowserError("missing_file_message must not be empty")
+    if not isinstance(not_file_message, str):
+        raise HyperbrowserError("not_file_message must be a string")
+    if not not_file_message.strip():
+        raise HyperbrowserError("not_file_message must not be empty")
     try:
         normalized_path = os.fspath(file_path)
     except HyperbrowserError:

tests/test_file_utils.py

@@ -20,6 +20,56 @@ def test_ensure_existing_file_path_accepts_existing_file(tmp_path: Path):
     assert normalized_path == str(file_path)
 
 
+def test_ensure_existing_file_path_rejects_non_string_missing_message(tmp_path: Path):
+    file_path = tmp_path / "file.txt"
+    file_path.write_text("content")
+
+    with pytest.raises(HyperbrowserError, match="missing_file_message must be a string"):
+        ensure_existing_file_path(
+            str(file_path),
+            missing_file_message=123,  # type: ignore[arg-type]
+            not_file_message="not-file",
+        )
+
+
+def test_ensure_existing_file_path_rejects_blank_missing_message(tmp_path: Path):
+    file_path = tmp_path / "file.txt"
+    file_path.write_text("content")
+
+    with pytest.raises(
+        HyperbrowserError, match="missing_file_message must not be empty"
+    ):
+        ensure_existing_file_path(
+            str(file_path),
+            missing_file_message="   ",
+            not_file_message="not-file",
+        )
+
+
+def test_ensure_existing_file_path_rejects_non_string_not_file_message(tmp_path: Path):
+    file_path = tmp_path / "file.txt"
+    file_path.write_text("content")
+
+    with pytest.raises(HyperbrowserError, match="not_file_message must be a string"):
+        ensure_existing_file_path(
+            str(file_path),
+            missing_file_message="missing",
+            not_file_message=123,  # type: ignore[arg-type]
+        )
+
+
+def test_ensure_existing_file_path_rejects_blank_not_file_message(tmp_path: Path):
+    file_path = tmp_path / "file.txt"
+    file_path.write_text("content")
+
+    with pytest.raises(HyperbrowserError, match="not_file_message must not be empty"):
+        ensure_existing_file_path(
+            str(file_path),
+            missing_file_message="missing",
+            not_file_message="  ",
+        )
+
+
 def test_ensure_existing_file_path_accepts_pathlike_inputs(tmp_path: Path):
     file_path = tmp_path / "pathlike-file.txt"
     file_path.write_text("content")