tests(cleanup): clarify destructor tests and add weakref-guarded variant

- Rename `testCallQtMethodInDel` to make intent explicit.
- Add `testCallQtMethodInDestructorWeakRefGuarded` to cover the pattern where
  `__del__` dereferences a `weakref` before calling a Qt method.

Author: jcfr

tests/PythonQtTestCleanup.cpp

@@ -44,7 +44,7 @@ void PythonQtTestCleanup::testQtEnum()
     ));
 }
 
-void PythonQtTestCleanup::testCallQtMethodInDel()
+void PythonQtTestCleanup::testCallQtMethodInDestructorOwnedQTimer()
 {
   QVERIFY(_helper->runScript(
     "import PythonQt.QtCore\n" \
@@ -59,6 +59,22 @@ void PythonQtTestCleanup::testCallQtMethodInDel()
     ));
 }
 
+void PythonQtTestCleanup::testCallQtMethodInDestructorWeakRefGuarded()
+{
+    QVERIFY(_helper->runScript(
+        "import weakref\n" \
+        "import PythonQt.QtCore\n" \
+        "class TimerWrapper(object):\n" \
+        "  def __init__(self):\n" \
+        "    self.timerWeakRef = weakref.ref(PythonQt.QtCore.QTimer())\n" \
+        "  def __del__(self):\n" \
+        "    if self.timerWeakRef():\n" \
+        "      self.timerWeakRef().setSingleShot(True)\n" \
+        "x = TimerWrapper()\n" \
+        "obj.setPassed()\n"
+        ));
+}
+
 void PythonQtTestCleanup::testSignalReceiverCleanup()
 {
   PythonQtObjectPtr main = PythonQt::self()->getMainModule();

tests/PythonQtTestCleanup.h

@@ -17,7 +17,8 @@ private Q_SLOTS:
   void cleanup();
 
   void testQtEnum();
-  void testCallQtMethodInDel();
+  void testCallQtMethodInDestructorOwnedQTimer();
+  void testCallQtMethodInDestructorWeakRefGuarded();
   void testSignalReceiverCleanup();
 
 private: