Ensure foreign window can be reparented out of contained window again

A foreign window embedded into a Qt hierarchy must also support
being removed from that window hierarchy.

Pick-to: 6.6
Change-Id: Id4d08079ff19d67a8989937bc72602e8bd14b31b
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

1 files changed, 8 insertions, 1 deletions

diff --git a/tests/auto/gui/kernel/qwindow/tst_foreignwindow.cpp b/tests/auto/gui/kernel/qwindow/tst_foreignwindow.cpp
index c42bb9d974..a43939a21b 100644
--- a/tests/auto/gui/kernel/qwindow/tst_foreignwindow.cpp
+++ b/tests/auto/gui/kernel/qwindow/tst_foreignwindow.cpp
@@ -81,10 +81,17 @@ void tst_ForeignWindow::embedForeignWindow()
     NativeWindow nativeWindow;
     QVERIFY(nativeWindow);
 
+    // Top level windows may not have 0 as their winId, e.g. on
+    // XCB the root window of the screen is used.
+    const auto originalParentWinId = nativeWindow.parentWinId();
+
     // As a prerequisite to that, we must be able to reparent the foreign window
     std::unique_ptr<QWindow> foreignWindow(QWindow::fromWinId(nativeWindow));
-    foreignWindow.release()->setParent(&parentWindow);
+    foreignWindow->setParent(&parentWindow);
     QTRY_COMPARE(nativeWindow.parentWinId(), parentWindow.winId());
+
+    foreignWindow->setParent(nullptr);
+    QTRY_COMPARE(nativeWindow.parentWinId(), originalParentWinId);
 }
 
 #include <tst_foreignwindow.moc>