Fix linting errors from updated Ruff version

tests/test_gui/test_gui_guimain.py

@@ -812,13 +812,13 @@ def testGuiMain_OpenClose(qtbot, monkeypatch, nwGUI, projPath, fncPath, mockRnd)
     # Handle broken index on project open
     nwGUI.closeProject()
     idxPath: Path = projPath / "meta" / nwFiles.INDEX_FILE
-    assert idxPath.read_text() != "{}"
-    idxPath.write_text("{}")
-    assert idxPath.read_text() == "{}"
+    assert idxPath.read_text(encoding="utf-8") != "{}"
+    idxPath.write_text("{}", encoding="utf-8")
+    assert idxPath.read_text(encoding="utf-8") == "{}"
 
     nwGUI.openProject(projPath)
     nwGUI.saveProject()
-    assert idxPath.read_text() != "{}"
+    assert idxPath.read_text(encoding="utf-8") != "{}"
     assert nwGUI.docEditor.docHandle == C.hSceneDoc
     assert nwGUI.docViewer.docHandle == C.hTitlePage
 

tests/test_gui/test_gui_theme.py

@@ -164,14 +164,14 @@ def testGuiTheme_Theme(qtbot, monkeypatch, nwGUI, tstPaths):
     # ===============
 
     mockTheme: Path = tstPaths.cnfDir / "themes" / "test.conf"
-    mockTheme.write_text(
+    mockTheme.write_text((
         "[Main]\n"
         "name = Test\n"
         "\n"
         "[Palette]\n"
         "window = 0, 0, 0\n"
         "text = 255, 255, 255\n"
-    )
+    ), encoding="utf-8")
     mainTheme._availThemes["test"] = mockTheme
 
     CONFIG.guiTheme = "test"