Add test coverage and fix a few minor things

tests/test_ext/test_ext_wheeleventfilter.py

@@ -0,0 +1,67 @@
+"""
+novelWriter – Wheel Event Filter Tester
+=======================================
+
+This file is a part of novelWriter
+Copyright 2018–2023, Veronica Berglyd Olsen
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <https://www.gnu.org/licenses/>.
+"""
+
+from PyQt5.QtCore import QEvent, QObject, QPoint, Qt
+import pytest
+
+from PyQt5.QtGui import QKeyEvent, QWheelEvent
+from PyQt5.QtWidgets import QWidget
+
+from novelwriter.extensions.wheeleventfilter import WheelEventFilter
+
+
+class MockWidget(QWidget):
+
+    def __init__(self):
+        super().__init__(None)
+        self.count = 0
+        return
+
+    def wheelEvent(self, event: QWheelEvent) -> None:
+        self.count += 1
+        return
+
+
+@pytest.mark.gui
+def testExtWheelEventFilter_Main():
+    """Test the WheelEventFilter class."""
+    obj = QObject()
+    widget = MockWidget()
+    eFilter = WheelEventFilter(widget)
+    assert widget.count == 0
+
+    # Sending a key event does nothing
+    event = QKeyEvent(QEvent.KeyPress, 1, Qt.ShiftModifier)
+    eFilter.eventFilter(obj, event)
+    assert widget.count == 0
+
+    # Sending a mouse wheel event forwards it
+    pos = QPoint(0, 0)
+    event = QWheelEvent(pos, pos, pos, pos, Qt.NoButton, Qt.NoModifier, Qt.NoScrollPhase, False)
+    eFilter.eventFilter(obj, event)
+    assert widget.count == 1
+
+    # But ignore if we're locked
+    eFilter._locked = True
+    eFilter.eventFilter(obj, event)
+    assert widget.count == 1
+
+# END Test testExtWheelEventFilter_Main