fix(tests): Make binary mapper test platform-independent

The test for the binary mapper was failing on Windows due to differences in path separators. This commit fixes the test by using os.path.join to construct the expected path, ensuring the test runs correctly on all platforms.

Author: bosd

tests/test_mapper.py

@@ -2,6 +2,7 @@
 
 import inspect
 import logging
+import os
 from typing import Any, Callable
 from unittest.mock import MagicMock, patch
 
@@ -434,7 +435,8 @@ def test_binary_with_path_prefix(mocker: MagicMock) -> None:
     )
     mapper_func = mapper.binary("col1", path_prefix="/my/path")
     mapper_func(LINE_SIMPLE, {})
-    mock_open.assert_called_once_with("/my/path/A", "rb")
+    expected_path = os.path.join("/my/path", "A")
+    mock_open.assert_called_once_with(expected_path, "rb")
 
 
 def test_m2o_att_name() -> None: