Check crop preview rendering and interrupted drags

tools/chatgui/tests/test_avatar_crop.cpp

@@ -6,6 +6,7 @@
 #include <QPushButton>
 #include <QTemporaryDir>
 #include <QWheelEvent>
+#include <QMouseEvent>
 #include <functional>
 #include <cmath>
 extern "C" {
@@ -83,6 +84,8 @@ private slots:
         QVERIFY(image.save(path)); QRectF crop;
         QVERIFY(edit(path, crop, nullptr, [&](QDialog*, QWidget* view, QPushButton* upload) {
             for (int i = 0; i < zoomSteps; i++) wheel(view, QPoint(0, 120));
+            const QImage rendered = view->grab().toImage();
+            QCOMPARE(rendered.pixelColor(rendered.width()/2, rendered.height()/2), QColor(Qt::green));
             upload->click();
         }));
         QVERIFY(std::isfinite(crop.x()) && std::isfinite(crop.y()) && std::isfinite(crop.width()) && std::isfinite(crop.height()));
@@ -102,6 +105,22 @@ private slots:
         QCOMPARE(crop, before);
     }
 
+    void lostLeftButtonStopsDrag() {
+        QTemporaryDir directory; QVERIFY(directory.isValid());
+        const QString path = directory.filePath("source.png"); QImage image(800, 400, QImage::Format_RGB32); image.fill(Qt::blue);
+        QVERIFY(image.save(path)); QRectF crop;
+        QVERIFY(edit(path, crop, nullptr, [](QDialog*, QWidget* view, QPushButton* upload) {
+            const QPoint center = view->rect().center(); QTest::mousePress(view, Qt::LeftButton, Qt::NoModifier, center);
+            for (Qt::MouseButtons buttons : {Qt::MouseButtons(), Qt::MouseButtons(Qt::LeftButton)}) {
+                const QPoint point = center + QPoint(240, 0);
+                QMouseEvent move(QEvent::MouseMove, point, view->mapToGlobal(point), Qt::NoButton, buttons, Qt::NoModifier);
+                QApplication::sendEvent(view, &move);
+            }
+            QTest::mouseRelease(view, Qt::LeftButton, Qt::NoModifier, center + QPoint(240, 0)); upload->click();
+        }));
+        QVERIFY(qAbs(crop.x() - .25) < 1e-8);
+    }
+
     void parentCanDisappearDuringLoad() {
         QPointer<QWidget> parent = new QWidget;
         const QRectF before(.1, .2, .3, .4); QRectF crop = before;