Clean up tst_qwidgetwindow

Rename TestWidget to PaintTestWidget, because this class tests only
whether paint event occurs.

Remove unused variables.

Remove reset() method, because there is no need to reset only one
variable in class method.

Change-Id: I8f442c73598e3431baf2b0433fefc157d3f10ea6
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>

tests/auto/widgets/kernel/qwidget_window/tst_qwidget_window.cpp

@@ -206,32 +206,20 @@ void tst_QWidget_window::tst_show_resize_hide_show()
 //    QCoreApplication::processEvents(QEventLoop::AllEvents, 1000);
 }
 
-class TestWidget : public QWidget
+class PaintTestWidget : public QWidget
 {
 public:
-    int m_first, m_next;
-    bool paintEventReceived;
+    int paintEventCount;
 
-    void reset(){ m_first = m_next = 0; paintEventReceived = false; }
-    bool event(QEvent *event)
+    explicit PaintTestWidget(QWidget *parent = Q_NULLPTR)
+        : QWidget(parent)
+        , paintEventCount(0)
+    {}
+
+    void paintEvent(QPaintEvent *event) Q_DECL_OVERRIDE
     {
-        switch (event->type()) {
-        case QEvent::WindowActivate:
-        case QEvent::WindowDeactivate:
-        case QEvent::Hide:
-        case QEvent::Show:
-            if (m_first)
-                m_next = event->type();
-            else
-                m_first = event->type();
-            break;
-        case QEvent::Paint:
-            paintEventReceived = true;
-            break;
-        default:
-            break;
-        }
-        return QWidget::event(event);
+        ++paintEventCount;
+        QWidget::paintEvent(event);
     }
 };
 
@@ -366,15 +354,15 @@ void tst_QWidget_window::tst_showWithoutActivating()
 
 void tst_QWidget_window::tst_paintEventOnSecondShow()
 {
-    TestWidget w;
+    PaintTestWidget w;
     w.show();
     w.hide();
 
-    w.reset();
+    w.paintEventCount = 0;
     w.show();
     QVERIFY(QTest::qWaitForWindowExposed(&w));
     QApplication::processEvents();
-    QTRY_VERIFY(w.paintEventReceived);
+    QTRY_VERIFY(w.paintEventCount > 0);
 }
 
 #ifndef QT_NO_DRAGANDDROP