Further improvements to test setup

tests/data/test_converter.py

@@ -1,6 +1,5 @@
 # pragma pylint: disable=missing-docstring, C0103
 import logging
-from pathlib import Path
 from shutil import copyfile
 
 import numpy as np

tests/data/test_trade_converter_kraken.py

@@ -1,5 +1,4 @@
 from datetime import datetime, timezone
-from pathlib import Path
 from shutil import copytree
 from unittest.mock import PropertyMock