Clean up top level window access and add coverage to shared data class

tests/tools.py

@@ -25,7 +25,7 @@ import shutil
 from pathlib import Path
 from datetime import datetime
 
-from PyQt5.QtWidgets import QDialog, QVBoxLayout, QWidget, qApp
+from PyQt5.QtWidgets import QDialog, QVBoxLayout, QWidget
 
 XML_IGNORE = ("<novelWriterXML", "<project")
 ODT_IGNORE = ("<meta:generator", "<meta:creation-date", "<dc:date", "<meta:editing")
@@ -114,14 +114,6 @@ def cmpFiles(
     return not diffFound
 
 
-def getGuiItem(name: str):
-    """Returns a QtWidget based on its objectName."""
-    for qWidget in qApp.topLevelWidgets():
-        if qWidget.objectName() == name:
-            return qWidget
-    return None
-
-
 def readFile(fileName: str | Path):
     """Returns the content of a file as a string."""
     with open(fileName, mode="r", encoding="utf-8") as inFile: