Test backing store is deleted after reparenting a visible native child widget

After the following sequence:
  * Create a TLW, parent1
  * Create a child of parent1, and make it a native widget
  * Create another TLW, parent2
  * Show parent1 and parent2
  * Reparent child so its parent is now parent2
  * Hide parent1
parent1's backing store should be deleted, when running on Symbian.

Task-number: QTBUG-12817
Reviewed-by: Jason Barron
(cherry picked from commit b5360eb223d5377beb62008fcc1da48f432dc8dd)

1 files changed, 37 insertions, 0 deletions

diff --git a/tests/auto/qwidget/tst_qwidget.cpp b/tests/auto/qwidget/tst_qwidget.cpp
index e6e8970..ba0be3e 100644
--- a/tests/auto/qwidget/tst_qwidget.cpp
+++ b/tests/auto/qwidget/tst_qwidget.cpp
@@ -9795,6 +9795,43 @@ void tst_QWidget::destroyBackingStoreWhenHidden()
     // Check that backing store was deleted
     WAIT_AND_VERIFY(0 == backingStore(lower));
     }
+
+    // 7. Reparenting of visible native child widget
+    {
+    QWidget parent1;
+    parent1.setAutoFillBackground(true);
+    parent1.setPalette(Qt::green);
+    parent1.setGeometry(50, 50, 100, 100);
+
+    QWidget *child = new QWidget(&parent1);
+    child->winId();
+    child->setAutoFillBackground(true);
+    child->setPalette(Qt::red);
+    child->setGeometry(10, 10, 30, 30);
+
+    QWidget parent2;
+    parent2.setAutoFillBackground(true);
+    parent2.setPalette(Qt::blue);
+    parent2.setGeometry(150, 150, 100, 100);
+
+    parent1.show();
+    QTest::qWaitForWindowShown(&parent1);
+    QVERIFY(0 != backingStore(parent1));
+
+    parent2.show();
+    QTest::qWaitForWindowShown(&parent2);
+    QVERIFY(0 != backingStore(parent2));
+
+    child->setParent(&parent2);
+    child->setGeometry(10, 10, 30, 30);
+    child->show();
+
+    parent1.hide();
+    WAIT_AND_VERIFY(0 == backingStore(parent1));
+
+    parent2.hide();
+    WAIT_AND_VERIFY(0 == backingStore(parent2));
+    }
 }
 
 #undef WAIT_AND_VERIFY