Made the autotest for drawing pixmaps with painter open more fail safe.

The autotest relies on QPixmap::grabWindow() which causes random CI
failures because it may capture bogus content if some other window
comes to foreground, focus is changed, etc. To overcome these false
positives the pixmap content comparison is now only done when the
captured content is one of the three possible images. If it is
anything else, we cannot verify so the case is skipped.

Task-number: QT-4002
Reviewed-by: TRUSTME

1 files changed, 23 insertions, 8 deletions

diff --git a/tests/auto/qpixmap/tst_qpixmap.cpp b/tests/auto/qpixmap/tst_qpixmap.cpp
index d103cb7423..0b2f527d0d 100644
--- a/tests/auto/qpixmap/tst_qpixmap.cpp
+++ b/tests/auto/qpixmap/tst_qpixmap.cpp
@@ -1904,27 +1904,42 @@ private:
 
 void tst_QPixmap::drawPixmapWhilePainterOpen()
 {
-    int size = 100;
+    const int delay = 1000;
+    const int size = 100;
+    const QColor colors[] = { Qt::red, Qt::blue, Qt::green };
+
     QPixmap pix(size, size);
-    pix.fill(Qt::red);
+    pix.fill(colors[0]);
 
     PixmapWidget w(pix);
     w.show();
     QTest::qWaitForWindowShown(&w);
-    QTest::qWait(1000);
+    QTest::qWait(delay);
 
     QPainter p(&pix);
-    p.fillRect(0, 0, size, size, Qt::blue);
+    p.fillRect(0, 0, size, size, colors[1]);
     w.update();
-    QTest::qWait(1000);
+    QTest::qWait(delay);
 
-    p.fillRect(0, 0, size, size, Qt::green);
+    p.fillRect(0, 0, size, size, colors[2]);
     w.update();
-    QTest::qWait(1000);
+    QTest::qWait(delay);
 
     QPixmap actual = QPixmap::grabWindow(w.effectiveWinId(), 0, 0, size, size);
 
-    QVERIFY(lenientCompare(actual, pix));
+    // If we captured some bogus content with grabWindow(), the comparison makes no sense
+    // because it cannot prove the feature is broken.
+    QPixmap guard(size, size);
+    bool matchesColors = false;
+    for (size_t i = 0; i < sizeof(colors) / sizeof(const QColor); ++i) {
+        guard.fill(colors[i]);
+        matchesColors |= lenientCompare(actual, guard);
+    }
+    if (!matchesColors) {
+        QSKIP("Skipping verification due to grabWindow() issue", SkipSingle);
+    } else {
+        QVERIFY(lenientCompare(actual, pix));
+    }
 }
 
 QTEST_MAIN(tst_QPixmap)