2 files changed, 49 insertions, 1 deletions

diff --git a/tests/auto/gui/kernel/qwindow/tst_foreignwindow.cpp b/tests/auto/gui/kernel/qwindow/tst_foreignwindow.cpp
index e7b05e7037..526abd6ea3 100644
--- a/tests/auto/gui/kernel/qwindow/tst_foreignwindow.cpp
+++ b/tests/auto/gui/kernel/qwindow/tst_foreignwindow.cpp
@@ -26,6 +26,9 @@ private slots:
 
     void embedForeignWindow();
     void embedInForeignWindow();
+
+    void destroyExplicitly();
+    void destroyWhenParentIsDestroyed();
 };
 
 void tst_ForeignWindow::fromWinId()
@@ -138,5 +141,50 @@ void tst_ForeignWindow::embedInForeignWindow()
     }
 }
 
+void tst_ForeignWindow::destroyExplicitly()
+{
+    NativeWindow nativeWindow;
+    QVERIFY(nativeWindow);
+
+    std::unique_ptr<QWindow> foreignWindow(QWindow::fromWinId(nativeWindow));
+    QVERIFY(foreignWindow->handle());
+
+    // Explicitly destroying a foreign window is a no-op, as
+    // the documentation claims that it "releases the native
+    // platform resources associated with this window.", which
+    // is not technically true for foreign windows.
+    auto *windowHandleBeforeDestroy = foreignWindow->handle();
+    foreignWindow->destroy();
+    QCOMPARE(foreignWindow->handle(), windowHandleBeforeDestroy);
+}
+
+void tst_ForeignWindow::destroyWhenParentIsDestroyed()
+{
+    QWindow parentWindow;
+
+    NativeWindow nativeWindow;
+    QVERIFY(nativeWindow);
+
+    std::unique_ptr<QWindow> foreignWindow(QWindow::fromWinId(nativeWindow));
+    foreignWindow->setParent(&parentWindow);
+    QTRY_COMPARE(nativeWindow.parentWinId(), parentWindow.winId());
+
+    // Reparenting into a window will result in creating it
+    QVERIFY(parentWindow.handle());
+
+    // Destroying the parent window of the foreign window results
+    // in destroying the foreign window as well, as the foreign
+    // window no longer has a parent it can be embedded in.
+    QVERIFY(foreignWindow->handle());
+    parentWindow.destroy();
+    QVERIFY(!foreignWindow->handle());
+
+    // But the foreign window can be recreated again, and will
+    // continue to be a native child of the parent window.
+    foreignWindow->create();
+    QVERIFY(foreignWindow->handle());
+    QTRY_COMPARE(nativeWindow.parentWinId(), parentWindow.winId());
+}
+
 #include <tst_foreignwindow.moc>
 QTEST_MAIN(tst_ForeignWindow)
diff --git a/tests/shared/nativewindow.h b/tests/shared/nativewindow.h
index 51d211704e..932d2d419a 100644
--- a/tests/shared/nativewindow.h
+++ b/tests/shared/nativewindow.h
@@ -238,7 +238,7 @@ WId NativeWindow::parentWinId() const
     xcb_query_tree_reply_t *tree = xcb_query_tree_reply(
         connection, xcb_query_tree(connection, m_handle), nullptr);
     const auto cleanup = qScopeGuard([&]{ free(tree); });
-    return tree->parent;
+    return tree ? tree->parent : 0;
 }
 
 bool NativeWindow::isParentOf(WId childWinId)