1 files changed, 108 insertions, 0 deletions
diff --git a/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp b/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp
index d5807c1958..27fbcc2b3b 100644
--- a/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp
+++ b/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp
@@ -248,6 +248,8 @@ private slots:
 #ifndef QT_NO_CURSOR
     void QTBUG_7438_cursor();
 #endif
+    void resizeContentsOnItemDrag_data();
+    void resizeContentsOnItemDrag();
 
 public slots:
     void dummySlot() {}
@@ -4960,5 +4962,111 @@ void tst_QGraphicsView::QTBUG_70255_scrollTo()
     QCOMPARE(point, QPoint(0, -500));
 }
 
+void tst_QGraphicsView::resizeContentsOnItemDrag_data()
+{
+    QTest::addColumn<Qt::Alignment>("alignment");
+    QTest::addColumn<Qt::Orientation>("orientation");
+    QTest::addRow("Center right") << Qt::Alignment(Qt::AlignCenter) << Qt::Horizontal;
+    QTest::addRow("Center down") << Qt::Alignment(Qt::AlignCenter) << Qt::Vertical;
+    QTest::addRow("BottomLeft right") << (Qt::AlignBottom | Qt::AlignLeft) << Qt::Horizontal;
+    QTest::addRow("TopRight down") << (Qt::AlignTop | Qt::AlignRight) << Qt::Vertical;
+}
+
+void tst_QGraphicsView::resizeContentsOnItemDrag()
+{
+    QFETCH(Qt::Alignment, alignment);
+    QFETCH(Qt::Orientation, orientation);
+
+    QGraphicsView view;
+    QGraphicsScene scene;
+    view.setFixedSize(200, 200);
+    view.setScene(&scene);
+
+    view.setAlignment(alignment);
+
+    class MovableItem : public QGraphicsEllipseItem
+    {
+    public:
+        using QGraphicsEllipseItem::QGraphicsEllipseItem;
+
+        QList<QPointF> scenePositions;
+
+    protected:
+        void mousePressEvent(QGraphicsSceneMouseEvent *event) override
+        {
+            scenePositions << event->scenePos();
+        }
+        void mouseMoveEvent(QGraphicsSceneMouseEvent *event) override
+        {
+            scenePositions << event->scenePos();
+            QGraphicsEllipseItem::mouseMoveEvent(event);
+        }
+    };
+
+    MovableItem item(-10, -10, 20, 20);
+    item.setFlags(QGraphicsItem::ItemIsMovable);
+    scene.addItem(&item);
+    view.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&view));
+
+    // Position the item near the relevant edge of the view, with a few pixels
+    // to go until the scrollbars should be showing.
+    if (orientation == Qt::Horizontal)
+        item.setPos(view.width() - item.rect().width() - 5, 0);
+    else
+        item.setPos(0, view.height() - item.rect().height() - 5);
+    QApplication::processEvents(); // queued connection  used to trigger recalculateContentSize
+    QPoint mousePos = view.mapFromScene(item.pos());
+
+    QTest::mousePress(view.viewport(), Qt::LeftButton, {}, mousePos);
+    QCOMPARE(item.scenePositions.count(), 1);
+    QCOMPARE(item.scenePositions.takeLast(), view.mapToScene(mousePos));
+
+    auto lastItemPos = item.pos();
+    auto lastScenePos = view.mapToScene(mousePos);
+    int overshoot = 0;
+    const QScrollBar *scrollBar = orientation == Qt::Horizontal
+                                ? view.horizontalScrollBar()
+                                : view.verticalScrollBar();
+    // Drag the item until the scroll bars become visible, and then for a few more pixels.
+    // Verify that the item doesn't jump when the scrollbar shows.
+    while (overshoot < 10) {
+        if (orientation == Qt::Horizontal)
+            mousePos.rx() += 1;
+        else
+            mousePos.ry() += 1;
+        QTest::mouseMove(view.viewport(), mousePos);
+        QApplication::processEvents(); // queued connection used to trigger recalculateContentSize
+        const bool scrollbarAvailable = scrollBar->maximum() > scrollBar->minimum();
+        bool allowMoreEvents = false;
+        if (scrollbarAvailable) {
+            if (!overshoot) {
+                QTRY_VERIFY(scrollBar->isVisible());
+                // scrollbar becoming visible triggers event replay, so we get more than one
+                allowMoreEvents = true;
+            }
+            ++overshoot;
+        }
+        if (allowMoreEvents)
+            QCOMPARE_GE(item.scenePositions.count(), 1);
+        else
+            QCOMPARE(item.scenePositions.count(), 1);
+        const auto scenePos = item.scenePositions.takeLast();
+        item.scenePositions.clear();
+
+        const auto same = orientation == Qt::Horizontal ? &QPointF::y : &QPointF::x;
+        const auto moved = orientation == Qt::Horizontal ? &QPointF::x : &QPointF::y;
+        QCOMPARE((item.pos().*same)(), (lastItemPos.*same)());
+        QCOMPARE_GE((item.pos().*moved)() - (lastItemPos.*moved)(), 1);
+        QCOMPARE_LE((item.pos().*moved)() - (lastItemPos.*moved)(), 2);
+        lastItemPos = item.pos();
+
+        QCOMPARE((scenePos.*same)(), (lastScenePos.*same)());
+        QCOMPARE_GE((scenePos.*moved)() - (lastScenePos.*moved)(), 1);
+        QCOMPARE_LE((scenePos.*moved)() - (lastScenePos.*moved)(), 2);
+        lastScenePos = scenePos;
+    }
+}
+
 QTEST_MAIN(tst_QGraphicsView)
 #include "tst_qgraphicsview.moc"